A Quantum Monte Carlo Approach to the Adiabatic Connection Method

TL;DR

This paper introduces a novel quantum Monte Carlo method for the adiabatic connection approach in density functional theory, enabling more accurate calculations of exchange-correlation effects in electron systems.

Contribution

It combines variational quantum Monte Carlo with constrained optimization to improve the realization of the adiabatic connection method in DFT.

Findings

Results for exchange-correlation hole and energy density in an electron gas with a cosine potential.

Comparison shows differences from local density and generalized gradient approximations.

Demonstrates improved accuracy in modeling electron correlation effects.

Abstract

We present a new method for realizing the adiabatic connection approach in density functional theory, which is based on combining accurate variational quantum Monte Carlo calculations with a constrained optimization of the ground state many-body wavefunction for different values of the Coulomb coupling constant. We use the method to study an electron gas in the presence of a cosine-wave potential. For this system we present results for the exchange-correlation hole and exchange-correlation energy density, and compare our findings with those from the local density approximation and generalized gradient approximation.