Quantum Monte Carlo simulations of solids

TLDR

Stochastic wave‑function methods directly treat quantum many‑body effects and serve as benchmarks for other techniques. The article presents variational and fixed‑node diffusion quantum Monte Carlo methods for calculating properties of many‑electron systems. These methods are intrinsically parallel, enabling simulations of systems with a thousand or more electrons, and the authors provide a pedagogical overview and applications to ground and excited states of solids and clusters. QMC yields more accurate results than density‑functional theory, deepening understanding of electronic correlation, and allows precise study of surfaces and defects.

Abstract

This article describes the variational and fixed-node diffusion quantum Monte Carlo methods and how they may be used to calculate the properties of many-electron systems. These stochastic wave-function-based approaches provide a very direct treatment of quantum many-body effects and serve as benchmarks against which other techniques may be compared. They complement the less demanding density-functional approach by providing more accurate results and a deeper understanding of the physics of electronic correlation in real materials. The algorithms are intrinsically parallel, and currently available high-performance computers allow applications to systems containing a thousand or more electrons. With these tools one can study complicated problems such as the properties of surfaces and defects, while including electron correlation effects with high precision. The authors provide a pedagogical overview of the techniques and describe a selection of applications to ground and excited states of solids and clusters.