Benchmark Quantum Monte Carlo calculations of the ground-state kinetic, interaction, and total energy of the three-dimensional electron gas

TL;DR

This paper presents advanced Quantum Monte Carlo calculations of the three-dimensional electron gas, accurately determining ground-state energies and separating kinetic and interaction contributions with improved methods and finite-size extrapolation.

Contribution

It introduces refined QMC techniques with backflow corrections and finite-size extrapolation to achieve lower and more accurate ground-state energies for the electron gas.

Findings

Lower energies than previous reports.

Significant difference in interaction energies between node types.

Accurate separation of kinetic and interaction energies.

Abstract

We report variational and diffusion Quantum Monte Carlo ground-state energies of the three-dimensional electron gas using a model periodic Coulomb interaction and backflow corrections for N=54, 102, 178, and 226 electrons. We remove finite-size effects by extrapolation and we find lower energies than previously reported. Using the Hellman-Feynman operator sampling method introduced in Phys. Rev. Lett. 99, 126406 (2007), we compute accurately, within the fixed-node pproximation, the separate kinetic and interaction contributions to the total ground-state energy. The difference between the interaction energies obtained from the original Slater-determinant nodes and the backflow-displaced nodes is found to be considerably larger than the difference between the corresponding kinetic energies.