Diffusion Monte Carlo with lattice regularization

TL;DR

This paper presents a novel lattice regularization scheme for quantum Monte Carlo calculations that improves accuracy and consistency in electronic structure simulations by discretizing the kinetic term with an irrational mesh size ratio.

Contribution

The authors introduce a lattice regularization method using an irrational mesh size ratio, enabling non-local potentials to be included variationally in quantum Monte Carlo.

Findings

Enhanced accuracy over previous non-variational methods

Consistent inclusion of non-local potentials

Approach approaches the continuous limit as mesh size decreases

Abstract

We introduce an efficient lattice regularization scheme for quantum Monte Carlo calculations of realistic electronic systems. The kinetic term is discretized by a finite difference Laplacian with two mesh sizes, a and a', where a'/a is an irrational number so that the electronic coordinates are not defined on a particular lattice but on the continuous configuration space. The regularized Hamiltonian goes to the continuous limit for a -> 0 and provides several advantages. In particular, it allows the inclusion of non-local potentials in a consistent variational scheme, substantially improving the accuracy upon previous non-variational approaches.