Progress in Monte Carlo calculations of Fermi systems: normal liquid 3He

TL;DR

This paper advances Monte Carlo techniques to accurately model the equation of state of liquid helium-3, demonstrating that optimized backflow correlations yield results in excellent agreement with experiments.

Contribution

It introduces an improved Monte Carlo approach combining fixed-node, released-node, and analytical nodal surface optimization for Fermi systems.

Findings

Backflow correlations are sufficient for accurate equations of state.

Method achieves high agreement with experimental data.

Systematic nodal surface improvement enhances calculation precision.

Abstract

The application of the diffusion Monte Carlo method to a strongly interacting Fermi system as normal liquid $^3$He is explored. We show that the fixed-node method together with the released-node technique and a systematic method to analytically improve the nodal surface constitute an efficient strategy to improve the calculation up to a desired accuracy. This methodology shows unambiguously that backflow correlations, when properly optimized, are enough to generate an equation of state of liquid $^3$He in excellent agreement with experimental data from equilibrium up to freezing.