Short-time Behaviour and Criticality of Driven Lattice Gases

TL;DR

This paper investigates the early-time critical behavior of driven and undriven lattice gases using Monte Carlo simulations, revealing a universal Gaussian transverse fluctuation behavior described by an effective continuum theory.

Contribution

It demonstrates that short-time dynamics of driven and undriven lattice gases are governed by a universal Gaussian fluctuation behavior, regardless of stationary state properties.

Findings

Short-time dynamics are described by an effective continuum theory.

Transverse fluctuations are Gaussian in early-time evolution.

Driven and undriven models exhibit identical short-time behavior.

Abstract

The nonequilibrium short-time critical behaviors of driven and undriven lattice gases are investigated via Monte Carlo simulations in two spatial dimensions starting from a fully disordered initial configuration. In particular, we study the time evolution of suitably defined order parameters, which account for the strong anisotropy introduced by the homogeneous drive. We demonstrate that, at short times, the dynamics of all these models is unexpectedly described by an effective continuum theory in which transverse fluctuations, i.e., fluctuations averaged along the drive, are Gaussian, irrespective of this being actually the case in the stationary state. Strong numerical evidence is provided, in remarkable agreement with that theory, both for the driven and undriven lattice gases, which therefore turn out to display the same short-time dynamics.