Steady States of a Nonequilibrium Lattice Gas

TL;DR

This study uses Monte Carlo simulations to explore the phase behavior of a driven nonequilibrium lattice gas with two particle types, revealing a complex phase diagram with homogeneous and ordered phases, including a bicritical point.

Contribution

It provides the first detailed phase diagram of a nonequilibrium lattice gas with multiple particle types and interactions, highlighting novel phase transition features.

Findings

Identified three distinct phases: homogeneous and two ordered phases.

Mapped phase boundaries, including continuous and first-order transitions.

Discovered a nonequilibrium bicritical point where phase boundaries merge.

Abstract

We present a Monte Carlo study of a lattice gas driven out of equilibrium by a local hopping bias. Sites can be empty or occupied by one of two types of particles, which are distinguished by their response to the hopping bias. All particles interact via excluded volume and a nearest-neighbor attractive force. The main result is a phase diagram with three phases: a homogeneous phase, and two distinct ordered phases. Continuous boundaries separate the homogeneous phase from the ordered phases, and a first-order line separates the two ordered phases. The three lines merge in a nonequilibrium bicritical point.