Физика низких температур, 2007, № 09
http://dspace.nbuv.gov.ua:80/handle/123456789/118295
2019-12-09T08:49:50ZFine structure of critical opalescence spectra
http://dspace.nbuv.gov.ua:80/handle/123456789/120940
Fine structure of critical opalescence spectra
Sushko, M.Ya.
The effect of the 1.5-scattering mechanism on the time and temperature behavior of the electric field
autocorrelation function for the light wave scattered from fluids has been studied for the case where the order-
parameter fluctuations obey the diffusion-like kinetics with spatially-dependent kinetic coefficient. The
leading contributions to the relevant static correlation functions of the order-parameter fluctuations were
obtained by using the Ginzburg–Landau model with a cubic term, and then evaluated with the use of the
Gaussian uncoupling for many-point correlation functions and the Ornstein–Zernicke form for the pair correlation
function. It is shown that the presence of the 1.5-scattering effects in the overall scattering pattern
may be detected in the form of a small but noticeable deviation from exponential decay of the total electric
field autocorrelation function registered experimentally near the critical point. Obtained with the standard
methods of analysis, the effective halfwidth of the corresponding spectrum can reveal a stronger temperature
dependence and a multiplicative renormalization as compared to the halfwidth of the spectrum of the
pair correlator.
2007-01-01T00:00:00ZNonequilibrium statistical operators for systems with finite lifetime
http://dspace.nbuv.gov.ua:80/handle/123456789/120939
Nonequilibrium statistical operators for systems with finite lifetime
Ryazanov, V.V.
A family of nonequilibrium statistical operators (NSO) is introduced which differ by the system lifetime
distribution over which the quasiequilibrium (relevant) distribution is averaged. This changes the form of
the source in the Liouville equation, as well as the expressions for the kinetic coefficients, average fluxes,
and kinetic equations obtained with use of NSO. The difference from the Zubarev form of NSO is of the order
of the reciprocal lifetime of a system.
2007-01-01T00:00:00ZA Monte Carlo study of the Falicov–Kimball model in the perturbative regime
http://dspace.nbuv.gov.ua:80/handle/123456789/120938
A Monte Carlo study of the Falicov–Kimball model in the perturbative regime
Musiał, G.; Dębski, L.; Wojtkiewicz, J.
Finite-temperature properties of the Falicov–Kimball model on the square lattice have been studied in
the perturbative regime, i.e. for t/U << 1, where t is the hopping constant and U denotes the Coulomb interaction
strength. In our study, we have determined the phase diagram of the model in the second-order of the
perturbation theory, where the antiferromagnetic Ising model in the magnetic field emerges. In the fourth-order,
where our model constitutes the Ising model with more complicated frustrated antiferromagnetic interactions,
the sketch of the phase diagram was established. The Monte Carlo method was employed and the behavior
of Binder cumulants based on the order parameters was analyzed to determine the type of ordering
and phase boundaries in the diagram.
2007-01-01T00:00:00ZCollective excitations in dynamics of liquids: a «toy» dynamical model for binary mixtures
http://dspace.nbuv.gov.ua:80/handle/123456789/120937
Collective excitations in dynamics of liquids: a «toy» dynamical model for binary mixtures
Bryk, T.; Mryglod, I.M.
We propose a new «toy» dynamical model that permits us to derive analytical expressions for dispersion
of two branches of «bare» propagating collective excitations in binary disordered systems in the whole range
of wavenumbers. These expressions are used for the analysis of dependence of dispersion curves on mass ratio
and concentration at fixed density of the system. An effect of hybridization of two branches is discussed
in terms of mode contributions to time correlation functions. This allows us to estimate the regions with
dominant types of coherent or partial dynamics.
2007-01-01T00:00:00Z