Accelerated nuclear quantum effects sampling with open path integrals

TL;DR

This paper demonstrates that open path integral Monte Carlo simulations significantly reduce autocorrelation times in double well models, offering a faster approach to sampling nuclear quantum effects when the ground state approximation is valid.

Contribution

It introduces the use of open path integrals to accelerate nuclear quantum effects sampling, supported by theoretical explanation and numerical evidence.

Findings

Open path integrals reduce autocorrelation times in double well models.

Instantons act as transition states explaining the efficiency.

Applicable when ground state approximation holds.

Abstract

We numericaly demonstrate that, in double well models, the autocorrelation time of open path integral Monte Carlo simulations can be much smaller compared to standard ones using ring polymers. We also provide an intuitive explanation based on the role of instantons as transition states of the path integral pseudodynamics. Therefore we propose that, in all cases when the ground state approximation to the finite temperature partition function holds, open path integral simulations can be used to accelerate the sampling in realistic simulations aimed to explore nuclear quantum effects.