Linear-scaling quantum Monte Carlo with non-orthogonal localized orbitals

TL;DR

This paper introduces a simplified reformulation of quantum Monte Carlo that achieves linear scaling with system size using non-orthogonal localized orbitals, improving efficiency over previous methods like MLWO.

Contribution

The authors present a new linear-scaling QMC method based on non-orthogonal localized orbitals, offering a simpler alternative to MLWO-based approaches.

Findings

Linear-scaling performance demonstrated on MgO.

The new method outperforms MLWO in tests.

Implications for large complex systems discussed.

Abstract

We have reformulated the quantum Monte Carlo (QMC) technique so that a large part of the calculation scales linearly with the number of atoms. The reformulation is related to a recent alternative proposal for achieving linear-scaling QMC, based on maximally localized Wannier orbitals (MLWO), but has the advantage of greater simplicity. The technique we propose draws on methods recently developed for linear-scaling density functional theory. We report tests of the new technique on the insulator MgO, and show that its linear-scaling performance is somewhat better than that achieved by the MLWO approach. Implications for the application of QMC to large complex systems are pointed out.