Monte Carlo simulations of the electron short-range quantum ordering in Coulomb systems: Reducing the "fermionic sign problem"

TL;DR

This paper introduces a new path integral method that mitigates the fermionic sign problem, enabling the observation of short-range quantum ordering of electrons in Coulomb systems through Monte Carlo simulations.

Contribution

A novel path integral representation that reduces the fermionic sign problem in Monte Carlo simulations of electron systems at finite temperatures.

Findings

Observation of short-range quantum ordering of electrons

Demonstration of the method's effectiveness in plasma and electron gas

Detection of exchange excitons not seen in previous simulations

Abstract

To account for the interference effects of the Coulomb and exchange interactions of electrons a new path integral representation of the density matrix has been developed in the canonical ensemble at finite temperatures. The developed representation allows to reduce the notorious ``fermionic sign problem'' in the Monte Carlo simulations of fermionic systems. The obtained results for pair distribution functions in plasma and uniform electron gas demonstrate the short-range quantum ordering of electrons associated with exchange excitons in the literature. This fine physical effect was not observed earlier in standard path integral Monte Carlo simulations.