Spin-Orbit Interactions in Electronic Structure Quantum Monte Carlo

TL;DR

This paper introduces a generalized fixed-phase diffusion Monte Carlo method for systems with spin-dependent Hamiltonians, enabling accurate quantum simulations of spin-orbit interactions in atomic and molecular systems.

Contribution

It extends quantum Monte Carlo techniques to explicitly include spin-orbit interactions, broadening their applicability to spin-related quantum phenomena.

Findings

Method achieves accuracy comparable to fixed-node approaches.

Applicable to atomic and molecular systems with spin-dependent Hamiltonians.

Enables new research in spin-related quantum effects.

Abstract

We develop generalization of the fixed-phase diffusion Monte Carlo method for Hamiltonians which explicitly depend on particle spins such as for spin-orbit interactions. The method is formulated in zero variance manner and is similar to treatment of nonlocal operators in commonly used static- spin calculations. Tests on atomic and molecular systems show that it is very accurate, on par with the fixed-node method. This opens electronic structure quantum Monte Carlo methods to a vast research area of quantum phenomena in which spin-related interactions play an important role.