486 research outputs found
Relativistic diffusive motion in random electromagnetic fields
We show that the relativistic dynamics in a Gaussian random electromagnetic
field can be approximated by the relativistic diffusion of Schay and Dudley.
Lorentz invariant dynamics in the proper time leads to the diffusion in the
proper time. The dynamics in the laboratory time gives the diffusive transport
equation corresponding to the Juettner equilibrium at the inverse temperature
\beta^{-1}=mc^{2}. The diffusion constant is expressed by the field strength
correlation function (Kubo's formula).Comment: the version published in JP
Signal at subleading order in lattice HQET
We discuss the correlators in lattice HQET that are needed to go beyond the
static theory. Based on our implementation in the Schr\"odinger functional we
focus on their signal-to-noise ratios and check that a reasonable statistical
precision can be reached in quantities like and .Comment: 3 pages, Lattice2004(heavy), v2: corrected definition of X^{kin/spin
Commuting quantum transfer matrix approach to intrinsic Fermion system: Correlation length of a spinless Fermion model
The quantum transfer matrix (QTM) approach to integrable lattice Fermion
systems is presented. As a simple case we treat the spinless Fermion model with
repulsive interaction in critical regime. We derive a set of non-linear
integral equations which characterize the free energy and the correlation
length of for arbitrary particle density at any finite
temperatures. The correlation length is determined by solving the integral
equations numerically. Especially in low temperature limit this result agrees
with the prediction from conformal field theory (CFT) with high accuracy.Comment: 17 page
Collision Thermalization of Nucleons in Relativistic Heavy-Ion Collisions
We consider a possible mechanism of thermalization of nucleons in
relativistic heavy-ion collisions. Our model belongs, to a certain degree, to
the transport ones; we investigate the evolution of the system created in
nucleus-nucleus collision, but we parametrize this development by the number of
collisions of every particle during evolution rather than by the time variable.
We based on the assumption that the nucleon momentum transfer after several
nucleon-nucleon (-hadron) elastic and inelastic collisions becomes a random
quantity driven by a proper distribution. This randomization results in a
smearing of the nucleon momenta about their initial values and, as a
consequence, in their partial isotropization and thermalization. The trial
evaluation is made in the framework of a toy model. We show that the proposed
scheme can be used for extraction of the physical information from experimental
data on nucleon rapidity distribution.Comment: 13 pages, 8 figure
The q-deformed Bose gas: Integrability and thermodynamics
We investigate the exact solution of the q-deformed one-dimensional Bose gas
to derive all integrals of motion and their corresponding eigenvalues. As an
application, the thermodynamics is given and compared to an effective field
theory at low temperatures.Comment: 10 pages, 6 figure
Energy and entropy of relativistic diffusing particles
We discuss energy-momentum tensor and the second law of thermodynamics for a
system of relativistic diffusing particles. We calculate the energy and entropy
flow in this system. We obtain an exact time dependence of energy, entropy and
free energy of a beam of photons in a reservoir of a fixed temperature.Comment: 14 pages,some formulas correcte
Linearized Kompaneetz equation as a relativistic diffusion
We show that Kompaneetz equation describing photon diffusion in an
environment of an electron gas, when linearized around its equilibrium
distribution, coincides with the relativistic diffusion discussed in recent
publications. The model of the relativistic diffusion is related to soluble
models of imaginary time quantum mechanics. We suggest some non-linear
generalizations of the relativistic diffusion equation and their astrophysical
applications (in particular to the Sunyaev-Zeldovich effect).Comment: 12 page
Integrability of quantum chains: theory and applications to the spin-1/2 chain
In this contribution we review the theory of integrability of quantum systems
in one spatial dimension. We introduce the basic concepts such as the
Yang-Baxter equation, commuting currents, and the algebraic Bethe ansatz. Quite
extensively we present the treatment of integrable quantum systems at finite
temperature on the basis of a lattice path integral formulation and a suitable
transfer matrix approach (quantum transfer matrix). The general method is
carried out for the seminal model of the spin-1/2 chain for which
thermodynamic properties like specific heat, magnetic susceptibility and the
finite temperature Drude weight of the thermal conductivity are derived
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