Searcharxiv⌕ Search

arXiv subjects

Alexander I. Olemskoi

Publications and source records attributed to Alexander I. Olemskoi.

13 recordsLinked to original sources
arXiv2003

Phase transition within deformed Ising model

Deformation of Ising Hamiltonian by means of replacing a site spin $s_i$ by $s_i^q$ and statistics generalization with help of the substituting deformed probability $p_i^q$ instead of $p_i$ are studied jointly within mean--field scheme. Such deformed model is shown to be related to the phase transition of the second order with unusual set of critical indices depending essentially on the deformation parameter $q$. Scaling relations turn out to be invariant with respect to the deformation.

cond-mat.stat-mech↗
arXiv2000

Two Simple Approaches to Sol-Gel Transition

We represent a theory of polymer gelation as an analogue of liquid-glass transition in which elastic fields of stress and strain shear components appear spontaneously as a consequence of the cross-linking of macromolecules. This circumstance is explained on the basis of obvious combinatoric arguments as well as a synergetic Lorenz system, where the strain acts as an order parameter, a conjugate field is reduced to the elastic stress, and the number of cross-links is a control parameter. Both the combinatoric and synergetic approaches show that an anomalous slow dependence of the shear modulus on the number of cross-links is obtained.

cond-mat.stat-mech↗
arXiv2000

Field theory of avalanche formation

Self-organizing system is studied whose behavior is governed by field of an order parameter, a fluctuation amplitude of conjugate field and a couple of Grassmannian conjugated fields that define the entropy as a control parameter. Within the framework of self-consistent approach the dependencies of macro- and microscopic susceptibilities as well as memory and nonergodicity parameters are determined as a functions of the intensities of thermal and quenched disorders. Making use of the sandpile model shows that proposed scheme determines the conditions of avalanches formation in self-organized criticality phenomena.

cond-mat.stat-mech↗
arXiv2000

Gauge theory of self-similar system

On the basis of a dilatation invariant Lagrangian, governed equations are determined for probability density and gauge potential of the non-stationary self-similar stochastic system. It is shown that an automodel regime is observed at small time interval determined by the Tsallis' parameter $q>1$. An exponential falling down happens at large time where the dilatation parameter and the partial scale tend to constant values.

cond-mat.stat-mech↗
arXiv1999

Evolution of the System with Singular Multiplicative Noise

The governed equations for the order parameter, one-time and two-time correlators are obtained on the basis of the Langevin equation with the white multiplicative noise which amplitude $x^{a}$ is determined by an exponent $0 1/2$, when the system is disordered, the correlator behaves non-monotonically in the course of time, whereas the autocorrelator is increased monotonically. At $a<1/2$ the phase portrait of the system evolution divides into two domains: at small initial values of the order parameter, the system evolves to a disordered state, as above; within the ordered domain it is attracted to the point having the finite values of the autocorrelator and order parameter. The long-time asymptotes are defined to show that, within the disordered domain, the autocorrelator decays hyperbolically and the order parameter behaves as the power-law function with fractional exponent $-2(1-a)$. Correspondingly, within the ordered domain, the behavior of both dependencies is exponential with an index proportional to $-t\ln t$.

cond-mat.stat-mech↗
arXiv1999

Supersymmetry Theory of Disordered Heteropolymers

The effective motion equation that describes the different monomer alternation along the heteropolymer chain is proposed. On its basis the supersymmetry field scheme that allows to obtain the equations for the structure factor and Green function is built up. The memory and ergodicity breaking effects are investigated depending on the temperature and quenched disorder of the monomer alternation. The phase diagram that determines the existence of the non-ergodic and freezing states is provided.

cond-mat.stat-mech↗
arXiv1999

Statistical theory of hierarchical avalanche ensemble

The statistical ensemble of avalanche intensities is considered to investigate diffusion in ultrametric space of hierarchically subordinated avalanches. The stationary intensity distribution and the steady-state current are obtained. The critical avalanche intensity needed to initiate the global avalanche formation is calculated depending on noise intensity. The large time asymptotic for the probability of the global avalanche appearance is derived.

cond-mat.stat-mech↗
arXiv1999

Fractional-differential equations of motion

An elementary system leading to the notions of fractional integrals and derivatives is considered. Various physical situations whose description is associated with fractional differential equations of motion are discussed.

cond-mat.stat-mech↗
arXiv1999

Three-parameter model of a sand pile

The theory of a flux steady-state (avalanche) formation is presented for the simplest model of a real sand pile within the framework of Lorenz approach. The stationary values of sand velocity and sand pile slope are derived as functions of controlling parameter (externally driven sandpile slope). The additive noises of above values are taken into account to build the phase diagram, where the noise intensities determine a domain of the avalanche appearance. This domain shows to be crucial to the noise intensity of vertical component of sand velocity.

cond-mat.stat-mech↗
arXiv1999

Supersymmetric Field Theory of Non-Equilibrium Thermodynamic System

On the basis of Langevin equation the optimal SUSY field scheme is formulated to discribe a non-equilibrium thermodynamic system with quenched disorder and non-ergodicity effects. Thermodynamic and isothermal susceptibilities, memory parameter and irreversible response are determined at different temperatures and quenched disorder intensities.

cond-mat.stat-mech↗
arXiv1998

Supersymmetry approach to the random heteropolymer theory

The effective equation of motion that describes the different monomer alternation along the heteropolymer chain is proposed. On this basis the supersymmetry field scheme is built up to analyze memory and ergodicity breaking effects.

cond-mat.stat-mech↗