Hartree shift in unitary Fermi gases

TL;DR

This paper calculates the Hartree energy shift in a unitary Fermi gas, accounting for momentum dependence, and extends the theory to spin-imbalanced systems to determine polaron properties, aligning well with experimental data.

Contribution

It introduces a method to compute the Hartree shift at unitarity considering momentum dependence and extends the framework to spin-imbalanced gases for polaron analysis.

Findings

Hartree shift remains finite at unitarity due to explicit momentum dependence

The extended theory accurately predicts polaron properties in spin-imbalanced gases

Results agree with more complex theories and experimental measurements

Abstract

The Hartree energy shift is calculated for a unitary Fermi gas. By including the momentum dependence of the scattering amplitude explicitly, the Hartree energy shift remains finite even at unitarity. Extending the theory also for spin-imbalanced systems allows calculation of polaron properties. The results are in good agreement with more involved theories and experiments.