Accelerated sampling by infinite swapping of path integral molecular dynamics with surface hopping

TL;DR

This paper introduces an infinite swapping approach for path integral molecular dynamics with surface hopping, significantly improving sampling efficiency in multi-level quantum systems by averaging over surface configurations.

Contribution

It develops a novel infinite swapping limit that combines surface hopping with mean-field path integral dynamics, along with a multiscale integrator for efficient sampling.

Findings

Infinite swapping greatly enhances sampling efficiency.

The proposed method connects surface hopping with mean-field dynamics.

Numerical results show substantial speedup over traditional methods.

Abstract

To accelerate the thermal equilibrium sampling of multi-level quantum systems, the infinite swapping limit of a recently proposed multi-level ring polymer representation is investigated. In the infinite swapping limit, the ring polymer evolves according to an averaged Hamiltonian with respect to all possible surface index configurations of the ring polymer, thus connects the surface hopping approach to the mean-field path integral molecular dynamics. A multiscale integrator for the infinite swapping limit is also proposed to enable efficient sampling based on the limiting dynamics. Numerical results demonstrate the huge improvement of sampling efficiency of the infinite swapping compared with the direct simulation of path integral molecular dynamics with surface hopping.