75 research outputs found
Thermo field hydrodynamic and kinetic equations of dense quantum nuclear systems
Basic equations of nonequilibrium thermo field dynamics of dense quantum
systems are presented. A formulation of nonequilibrium thermo field dynamics
has been performed using the nonequilibrium statistical operator method by
D.N.Zubarev. Hydrodynamic equations have been obtained in thermo field
representation. Two levels of the description of kinetics and hydrodynamics of
a dense nuclear matter are considered. The first one is a quantum system with
strongly coupled states, the second one is a quark-gluon plasma. Generalized
transfer equations of a consistent description of kinetics and hydrodynamics
have been obtained, as well as limiting cases are considered.Comment: 37 LaTeX2e pages, special sty-fil
Enskog-Landau kinetic equation for multicomponent mixture. Analytical calculation of transport coefficients
The Enskog-Landau kinetic equation is considered to describe non-equilibrium
processes of a mixture of charged hard spheres. This equation has been obtained
in our previous papers by means of the non-equilibrium statistical operator
method. The normal solution of this kinetic equation found in the first
approximation using the standard Chapman-Enskog method is given. On the basis
of the found solution the flows and transport coefficients have been
calculated. All transport coefficients for multicomponent mixture of spherical
Coulomb particles are presented analytically for the first time. Numerical
calculations of thermal conductivity and thermal diffusion coefficient are
performed for some specific mixtures of noble gases of high density. We compare
the calculations with those ones for point-like neutral and charged particles.Comment: 5 LaTeX2e pages, 2 eps-figure
A consistent description of kinetics and hydrodynamics of systems of interacting particles by means of the nonequilibrium statistical operator method
A statistical approach to a self-consistent description of kinetic and
hydrodynamic processes in systems of interacting particles is formulated on the
basis of the nonequilibrium statistical operator method by D.N.Zubarev. It is
shown how to obtain the kinetic equation of the revised Enskog theory for a
hard sphere model, the kinetic equations for multistep potentials of
interaction and the Enskog-Landau kinetic equation for a system of charged hard
spheres. The BBGKY hierarchy is analyzed on the basis of modified group
expansions. Generalized transport equations are obtained in view of a
self-consistent description of kinetics and hydrodynamics. Time correlation
functions, spectra of collective excitations and generalized transport
coefficients are investigated in the case of weakly nonequilibrium systems of
interacting particles.Comment: 64 LaTeX2e pages, 1 figure, special sty-files, additional font
Site-site memory equation approach in study of density/pressure dependence of translational diffusion coefficient and rotational relaxation time of polar molecular solutions: acetonitrile in water, methanol in water, and methanol in acetonitrile
We present results of theoretical study and numerical calculation of the
dynamics of molecular liquids based on combination of the memory equation
formalism and the reference interaction site model - RISM. Memory equations for
the site-site intermediate scattering functions are studied in the
mode-coupling approximation for the first order memory kernels, while
equilibrium properties such as site-site static structure factors are deduced
from RISM. The results include the temperature-density(pressure) dependence of
translational diffusion coefficients D and orientational relaxation times t for
acetonitrile in water, methanol in water and methanol in acetonitrile, all in
the limit of infinite dilution. Calculations are performed over the range of
temperatures and densities employing the SPC/E model for water and optimized
site-site potentials for acetonitrile and methanol. The theory is able to
reproduce qualitatively all main features of temperature and density
dependences of D and t observed in real and computer experiments. In
particular, anomalous behavior, i.e. the increase in mobility with density, is
observed for D and t of methanol in water, while acetonitrile in water and
methanol in acetonitrile do not show deviations from the ordinary behavior. The
variety exhibited by the different solute-solvent systems in the density
dependence of the mobility is interpreted in terms of the two competing origins
of friction, which interplay with each other as density increases: the
collisional and dielectric frictions which, respectively, increase and decrease
with increasing density.Comment: 13 pages, 8 eps-figures, 3 tables, RevTeX4-forma
Statistical-mechanical theory of ultrasonic absorption in molecular liquids
We present results of theoretical description of ultrasonic phenomena in
molecular liquids. In particular, we are interested in the development of
microscopical, i.e., statistical-mechanical framework capable to explain the
long living puzzle of the excess ultrasonic absorption in liquids. Typically,
ultrasonic wave in a liquid can be generated by applying the periodically
alternating external pressure with the angular frequency that corresponds to
the ultrasound. If the perturbation introduced by such process is weak - its
statistical-mechanical treatment can be done with the use of the linear
response theory. We treat the liquid as a system of interacting sites, so that
all the response/aftereffect functions as well as the energy dissipation and
generalized (wave-vector and frequency dependent) ultrasonic absorption
coefficient are obtained in terms of familiar site-site static and time
correlation functions such as static structure factors or intermediate
scattering functions. To express the site-site intermediate scattering
functions we refer to the site-site memory equations in the mode-coupling
approximation for the first-order memory kernels, while equilibrium properties
such as site-site static structure factors, direct and total correlation
functions are deduced from the integral equation theory of molecular liquids
known as RISM or one of its generalizations. All the formalism is phrased in a
general manner, hence the obtained results are expected to work for arbitrary
type of molecular liquid including simple, ionic, polar, and non-polar liquids.Comment: 14 pages, 1 eps-figure, RevTeX4-forma
- …