Phase Transitions in a Driven Lattice Gas with Anisotropic Interactions

TL;DR

This paper investigates phase transitions in a driven anisotropic lattice gas, revealing how the transition temperature shifts and the nature of phase transitions depend on interaction anisotropy and drive strength, using simulations and series expansions.

Contribution

It introduces a detailed analysis of non-equilibrium phase transitions in anisotropic driven lattice gases, combining Monte Carlo simulations with high temperature series techniques.

Findings

Transition temperature shifts can be positive or negative depending on interaction ratios.

Both first and second order phase transitions are observed under finite drives.

Phase diagram features can be partially predicted by correlation function analysis.

Abstract

The Ising lattice gas, with its well known equilibrium properties, displays a number of surprising phenomena when driven into non-equilibrium steady states. We study such a model with anisotropic interparticle interactions ($J_{\Vert }\neq J_{\bot}$), using both Monte Carlo simulations and high temperature series techniques. Under saturation drive, the shift in the transition temperature can be both positive and negative, depending on the ratio $J_{\Vert }/J_{\bot}$! For finite drives, both first and second order transitions are observed. Some aspects of the phase diagram can be predicted by investigating the two point correlation function at the first non-trivial order of a high temperature series expansion.