Metastability, nucleation, and noise-enhanced stabilization out of equilibrium

TL;DR

This paper investigates how nonequilibrium perturbations affect metastability and nucleation in a 2D Ising model, revealing noise-enhanced stability and domain wall resonance due to complex fluctuation interactions.

Contribution

It introduces a nonequilibrium potential framework to describe metastable states and decay, and demonstrates noise-enhanced stability and reentrant surface tension behavior.

Findings

Noise-enhanced stability of metastable phases.

Resonant propagation of domain walls at low temperatures.

Reentrant surface tension behavior as a function of temperature.

Abstract

We study metastability and nucleation in a kinetic two-dimensional Ising model which is driven out of equilibrium by a small random perturbation of the usual dynamics at temperature T. We show that, at a mesoscopic/cluster level, a nonequilibrium potential describes in a simple way metastable states and their decay. We thus predict noise-enhanced stability of the metastable phase and resonant propagation of domain walls at low T. This follows from the nonlinear interplay between thermal and nonequilibrium fluctuations, which induces reentrant behavior of the surface tension as a function of T. Our results, which are confirmed by Monte Carlo simulations, can be also understood in terms of a Langevin equation with competing additive and multiplicative noises.