A modified hartree-fock approximation for the zero-temperature electron gas

Abstract

We present a nonperturbative, self-consistent calculation for the zero-temperature electron gas based on a modified Hartree-Fock approximation in which the Coulomb potential is replaced by a Debye screened potential. The single particle energy spectrum and the screening length are determined in a self-consistent manner; the resulting energy spectrum is used to compute the specific heat, the ground-state energy and the pressure. The specific heat compares favorably with that calculated by Hedin, but the correlation energy turns out to have the wrong sign. We compute the pressure in two different ways to check the thermodynamic consistency (in the sense of Baym) of the theory; in the metallic density region the deviation from thermodynamic consistency varies from 6% to 10%.