Expanded ensemble method for bubble nucleation

TL;DR

The paper introduces an expanded ensemble sampling method that overcomes barriers in simulating bubble nucleation during phase transitions, enabling efficient large-volume simulations.

Contribution

A novel expanded ensemble method is proposed to improve sampling efficiency in bubble nucleation simulations, surpassing limitations of existing techniques.

Findings

Effectively circumvents condensation barriers

Enables efficient large-volume simulations

Improves sampling of critical bubble formation

Abstract

In the absence of impurities and boundary effects, first order phase transitions are initiated by the nucleation of critical bubbles. In thermally driven transitions many systems can remain metastable for an extended time, possibly tens of orders of magnitude longer than typical microscopic timescales. In standard Markov chain Monte Carlo simulations of these systems the probability of critical bubbles can be too suppressed for the transition to happen in any practical simulation time. The computation can be accelerated by using modified sampling methods, for example multicanonical or Wang-Landau sampling. However, even using these methods, there remains a condensation barrier which dramatically reduces the efficiency at large volumes. We present a novel sampling method, the method of expanded ensembles, which very effectively circumvents the condensation barrier and enables efficient simulations at large volumes.