Second-order interaction corrections to the Fermi surface and the quasiparticle properties of dipolar fermions in three dimensions

TL;DR

This paper computes second-order interaction effects on the Fermi surface and quasiparticle properties of 3D dipolar fermions, revealing small corrections to Hartree-Fock results but earlier instability predictions.

Contribution

It provides a second-order perturbative analysis of dipolar fermions, refining the understanding of their Fermi surface and stability limits.

Findings

Second-order corrections are less than 1% for Fermi surface properties.

Instability occurs at lower interaction strength when using second-order compressibility.

Hartree-Fock overestimates the stability threshold.

Abstract

We calculate the renormalized Fermi surface and the quasiparticle properties in the Fermi liquid phase of three-dimensional dipolar fermions to second order in the dipole-dipole interaction. Using parameters relevant to an ultracold gas of erbium atoms, we find that the second-order corrections typically renormalize the Hartree-Fock results by less than one percent. On the other hand, if we use the second-order correction to the compressibility to estimate the regime of stability of the system, the point of instability is already reached for a significantly smaller interaction strength than in the Hartree-Fock approximation.