4,991 research outputs found

    An explicit KO-degree map and applications

    Full text link
    The goal of this note is to study the analog in unstable A1{{\mathbb A}^1}-homotopy theory of the unit map from the motivic sphere spectrum to the Hermitian K-theory spectrum, i.e., the degree map in Hermitian K-theory. We show that "Suslin matrices", which are explicit maps from odd dimensional split smooth affine quadrics to geometric models of the spaces appearing in Bott periodicity in Hermitian K-theory, stabilize in a suitable sense to the unit map. As applications, we deduce that KiMW(F)=GWii(F)K^{MW}_i(F) = GW^i_i(F) for i3i \leq 3, which can be thought of as an extension of Matsumoto's celebrated theorem describing K2K_2 of a field. These results provide the first step in a program aimed at computing the sheaf πnA1(An0)\pi_{n}^{{\mathbb A}^1}({\mathbb A}^n \setminus 0) for n4n \geq 4.Comment: 36 Pages, Final version, to appear Journal of Topolog

    Harnack Inequality and Regularity for a Product of Symmetric Stable Process and Brownian Motion

    Full text link
    In this paper, we consider a product of a symmetric stable process in Rd\mathbb{R}^d and a one-dimensional Brownian motion in R+\mathbb{R}^+. Then we define a class of harmonic functions with respect to this product process. We show that bounded non-negative harmonic functions in the upper-half space satisfy Harnack inequality and prove that they are locally H\"older continuous. We also argue a result on Littlewood-Paley functions which are obtained by the α\alpha-harmonic extension of an Lp(Rd)L^p(\mathbb{R}^d) function.Comment: 23 page

    Charge diffusion constant in hot and dense hadronic matter - A Hadro-molecular-dynamic calculation

    Get PDF
    We evaluate charge diffusion constant of dense and hot hadronic matter based on the molecular dynamical method by using a hadronic collision generator which describes nuclear collisions at energies 10 < E < 100 GeV/A and satisfies detailed balance at low temperatures (T < 200 MeV). For the hot and dense hadronic matter of the temperature range, 100 < T < 200 MeV and baryon number density, 0.16 < nB < 0.32 fm^-3, charge diffusion constant D gradually increases from 0.5 fm c to 2 fm c with temperature and is almost independent of baryon number density. Based on the obtained diffusion constant we make simple discussions on the diffusion of charge fluctuation in ultrarelativistic nuclear collisions.Comment: 13 pages, 4 figure

    Beat-wave generation of plasmons in semiconductor plasmas

    Full text link
    It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap semiconductors (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas.Comment: 11 pages, LaTex, no figures, no macro

    Discrimination between two mechanisms of surface-scattering in a single-mode waveguide

    Full text link
    Transport properties of a single-mode waveguide with rough boundary are studied by discrimination between two mechanisms of surface scattering, the amplitude and square-gradient ones. Although these mechanisms are generically mixed, we show that for some profiles they can separately operate within non-overlapping intervals of wave numbers of scattering waves. This effect may be important in realistic situations due to inevitable long-range correlations in scattering profiles.Comment: 5 pages, 3 figure

    Axial anomaly: the modern status

    Full text link
    The modern status of the problem of axial anomaly in QED and QCD is reviewed. Two methods of the derivation of the axial anomaly are presented: 1) by splitting of coordinates in the expression for the axial current and 2) by calculation of triangle diagrams, where the anomaly arises from the surface terms in momentum space. It is demonstrated, that the equivalent formulation of the anomaly can be given, as a sum rule for the structure function in dispersion representation of three point function of AVV interaction. It is argued, that such integral representation of the anomaly has some advantages in the case of description of the anomaly by contribution of hadronic states in QCD. The validity of the t'Hooft consistency condition is discussed. Few examples of the physical application of the axial anomaly are given.Comment: 17 pages, 3 figures, to be published in International Journal of Modern Physics A, few minor correction were done, two references were adde

    Slow imbalance relaxation and thermoelectric transport in graphene

    Full text link
    We compute the electronic component of the thermal conductivity (TC) and the thermoelectric power (TEP) of monolayer graphene, within the hydrodynamic regime, taking into account the slow rate of carrier population imbalance relaxation. Interband electron-hole generation and recombination processes are inefficient due to the non-decaying nature of the relativistic energy spectrum. As a result, a population imbalance of the conduction and valence bands is generically induced upon the application of a thermal gradient. We show that the thermoelectric response of a graphene monolayer depends upon the ratio of the sample length to an intrinsic length scale l_Q, set by the imbalance relaxation rate. At the same time, we incorporate the crucial influence of the metallic contacts required for the thermopower measurement (under open circuit boundary conditions), since carrier exchange with the contacts also relaxes the imbalance. These effects are especially pronounced for clean graphene, where the thermoelectric transport is limited exclusively by intercarrier collisions. For specimens shorter than l_Q, the population imbalance extends throughout the sample; the TC and TEP asymptote toward their zero imbalance relaxation limits. In the opposite limit of a graphene slab longer than l_Q, at non-zero doping the TC and TEP approach intrinsic values characteristic of the infinite imbalance relaxation limit. Samples of intermediate (long) length in the doped (undoped) case are predicted to exhibit an inhomogeneous temperature profile, whilst the TC and TEP grow linearly with the system size. In all cases except for the shortest devices, we develop a picture of bulk electron and hole number currents that flow between thermally conductive leads, where steady-state recombination and generation processes relax the accumulating imbalance.Comment: 14 pages, 4 figure

    Generalized Robba rings

    Get PDF
    We prove that any projective coadmissible module over the locally analytic distribution algebra of a compact pp-adic Lie group is finitely generated. In particular, the category of coadmissible modules does not have enough projectives. In the Appendix a "generalized Robba ring" for uniform pro-pp groups is constructed which naturally contains the locally analytic distribution algebra as a subring. The construction uses the theory of generalized microlocalization of quasi-abelian normed algebras that is also developed there. We equip this generalized Robba ring with a self-dual locally convex topology extending the topology on the distribution algebra. This is used to show some results on coadmissible modules.Comment: with an appendix by Peter Schneider; revised; new titl

    Analysis of reaction dynamics at RHIC in a combined parton/hadron transport approach

    Get PDF
    We introduce a transport approach which combines partonic and hadronic degrees of freedom on an equal footing and discuss the resulting reaction dynamics. The initial parton dynamics is modeled in the framework of the parton cascade model, hadronization is performed via a cluster hadronization model and configuration space coalescence, and the hadronic phase is described by a microscopic hadronic transport approach. The resulting reaction dynamics indicates a strong influence of hadronic rescattering on the space-time pattern of hadronic freeze-out and on the shape of transverse mass spectra. Freeze-out times and transverse radii increase by factors of 2 - 3 depending on the hadron species.Comment: 10 pages, 4 eps figures include
    corecore