Momentum Distribution of a Fermi Gas in the Random Phase Approximation

Niels Benedikter, Sascha Lill

Published 2023-10-04Version 1

We consider a system of interacting fermions on the three-dimensional torus in the mean-field scaling limit. Our objective is computing the occupation number of the Fourier modes in a trial state obtained through the random phase approximation for the ground state. Our result shows that -- in the trial state -- the Fermi momentum does not depend on the interaction potential (it is universal), while the jump at the Fermi surface is as predicted by Daniel and Vosko.