4,991 research outputs found
An explicit KO-degree map and applications
The goal of this note is to study the analog in unstable -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 for ,
which can be thought of as an extension of Matsumoto's celebrated theorem
describing of a field. These results provide the first step in a program
aimed at computing the sheaf for .Comment: 36 Pages, Final version, to appear Journal of Topolog
Harnack Inequality and Regularity for a Product of Symmetric Stable Process and Brownian Motion
In this paper, we consider a product of a symmetric stable process in
and a one-dimensional Brownian motion in . 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
-harmonic extension of an function.Comment: 23 page
Charge diffusion constant in hot and dense hadronic matter - A Hadro-molecular-dynamic calculation
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
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
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
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
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
We prove that any projective coadmissible module over the locally analytic
distribution algebra of a compact -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-
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
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
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