A Generalized Parallel Replica Dynamics

TL;DR

This paper introduces a generalized parallel replica dynamics method that uses a Fleming-Viot particle system and convergence diagnostics to efficiently simulate long metastable molecular processes.

Contribution

It combines a Fleming-Viot particle system with convergence diagnostics to determine convergence and generate samples, enhancing parallel replica dynamics applicability.

Findings

Effective in systems with entropic barriers

Successfully applied to 2D Lennard-Jones cluster

Improves long-time molecular dynamics simulations

Abstract

Metastability is a common obstacle to performing long molecular dynamics simulations. Many numerical methods have been proposed to overcome it. One method is parallel replica dynamics, which relies on the rapid convergence of the underlying stochastic process to a quasi-stationary distribution. Two requirements for applying parallel replica dynamics are knowledge of the time scale on which the process converges to the quasi-stationary distribution and a mechanism for generating samples from this distribution. By combining a Fleming-Viot particle system with convergence diagnostics to simultaneously identify when the process converges while also generating samples, we can address both points. This variation on the algorithm is illustrated with various numerical examples, including those with entropic barriers and the 2D Lennard-Jones cluster of seven atoms.