Momentum distribution of the Uniform Electron Gas at finite temperature: Effects of spin-polarization

TL;DR

This study uses path integral Monte Carlo simulations to analyze how spin polarization influences the momentum distribution and related properties of the uniform electron gas at finite temperature, with implications for warm dense matter.

Contribution

It provides the first comprehensive quantification of spin effects on the momentum distribution of the UEG at finite temperature using PIMC simulations.

Findings

Spin polarization significantly affects the occupation of zero-momentum states.

Interaction effects on momentum distribution depend on spin polarization.

Results serve as benchmarks for future method development.

Abstract

We carry out extensive direct path integral Monte Carlo (PIMC) simulations of the uniform electron gas (UEG) at finite temperature for different values of the spin-polarization $\xi$. This allows us to unambiguously quantify the impact of spin-effects on the momentum distribution function $n(\mathbf{k})$ and related properties. We find that interesting physical effects like the interaction-induced increase in the occupation of the zero-momentum state $n(\mathbf{0})$ substantially depend on $\xi$. Our results further advance the current understanding of the UEG as a fundamental model system, and are of practical relevance for the description of transport properties of warm dense matter in an external magnetic field. All PIMC results are freely available online and can be used as a benchmark for the development of new methods and applications.