11,217 research outputs found
Thermodynamics of Van der Waals Fluids with quantum statistics
We consider thermodynamics of the van der Waals fluid of quantum systems. We
derive general relations of thermodynamic functions and parameters of any ideal
gas and the corresponding van der Waals fluid. This provides unambiguous
generalization of the classical van der Waals theory to quantum statistical
systems. As an example, we apply the van der Waals fluid with fermi statistics
to characterize the liquid-gas critical point in nuclear matter. We also
introduce the Bose-Einstein condensation in the relativistic van der Waals
boson gas, and argue, that it exhibits two-phase structure separated in space
Charmonium Production from the Secondary Collisions at LHC Energy
We consider the charmonium production in thermalized hadronic medium created
in ultrarelativistic heavy ion collisions at LHC energy.
  The calculations for the secondary  and  production by  annihilation are performed within a kinetic model taking into account the
space-time evolution of a longitudinally and transversely expanding medium. We
show that the secondary charmonium production appears almost entirely during
the mixed phase and it is very sensitive to the charmonium dissociation cross
section with co-moving hadrons. Within the most likely scenario for the
dissociation cross section of the  mesons their regeneration in the
hadronic medium will be negligible. The secondary production of  mesons
however, due to their large cross section above the threshold, can
substantially exceed the primary yield.Comment: ps file 11 
Topological calculation of the phase of the determinant of a non self-adjoint elliptic operator
We study the zeta-regularized determinant of a non self-adjoint elliptic
operator on a closed odd-dimensional manifold. We show that, if the spectrum of
the operator is symmetric with respect to the imaginary axis, then the
determinant is real and its sign is determined by the parity of the number of
the eigenvalues of the operator, which lie on the positive part of the
imaginary axis. It follows that, for many geometrically defined operators, the
phase of the determinant is a topological invariant. In numerous examples,
coming from geometry and physics, we calculate the phase of the determinants in
purely topological terms. Some of those examples were known in physical
literature, but no mathematically rigorous proofs and no general theory were
available until now.Comment: To appear in Communications of Mathematical Physic
From chemical freezeout to critical conditions in heavy ion collisions
We compare the statistical thermodynamics of hadron resonance gas with recent
LGT results at finite chemical potential. We argue that for  the
equation of state derived from
  Monte--Carlo simulations of two quark--flavor QCD at finite chemical
potential is consistent with that of a hadron resonance gas when applying the
same set of approximations as used in LGT calculations.
  We indicate the relation of chemical freezeout conditions obtained from a
detailed analysis of particle production in heavy ion collisions with the
critical conditions required for deconfinement. We argue that the position of a
hadron--quark gluon boundary line in temperature chemical potential plane can
be determined in terms of the resonance gas model by the condition of fixed
energy density.Comment: Talk given at BUDAPEST'2004 Workshop on 'Hot and Dense Matter in
  Relativistic Heavy Ion Physics', Budapest, March 24-27, 200
Viscosities in the Gluon-Plasma within a Quasiparticle Model
A phenomenological quasiparticle model, featuring dynamically generated
self-energies of excitation modes, successfully describes lattice QCD results
relevant for the QCD equation of state and related quantities both at zero and
non-zero net baryon density. Here, this model is extended to study bulk and
shear viscosities of the gluon-plasma within an effective kinetic theory
approach. In this way, the compatibility of the employed quasiparticle ansatz
with the apparent low viscosities of the strongly coupled deconfined gluonic
medium is shown.Comment: 4 pages, 1 figure. To appear in the conference proceedings for Quark
  Matter 2009, March 30 - April 4, Knoxville, Tennessee, US
Kurtosis and compressibility near the chiral phase transition
The properties of net quark number fluctuations in the vicinity of the QCD
chiral phase transition are discussed in terms of an effective chiral model in
the mean-field approximation. We focus on the ratio of the fourth- to second-
order cumulants (kurtosis) and the compressibility of the system and discuss
their dependence on the pion mass. It is shown that near the chiral phase
transition, both observables are sensitive to the value of . For
physical , the kurtosis exhibits a peak whereas the inverse
compressibility shows a dip at the pseudocritical temperature. These structures
disappear for large . Our results, obtained in an effective model with
two flavors, are qualitatively consistent with recent results of 2+1 flavor
lattice gauge theory. We also discuss the high- and low-temperature properties
of these observables and the role of the coupling of the quark degrees of
freedom to the Polyakov loop
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