Single-branch theory of ultracold Fermi gases with artificial Rashba spin-orbit coupling

TL;DR

This paper develops a simplified single-branch theoretical model for dilute ultracold Fermi gases with Rashba spin-orbit coupling, enabling easier analysis of their many-body physics.

Contribution

It introduces a renormalizable single-branch interacting theory for ultracold fermions with Rashba coupling, avoiding complex multi-channel treatments.

Findings

The theory is renormalizable in perturbation theory.

It models polarized fermions effectively without multi-channel complexity.

Provides a foundation for studying many-body physics in cold atoms with artificial vector potentials.

Abstract

We consider interacting ultracold fermions subject to Rashba spin-orbit coupling. We construct a single-branch interacting theory for the Fermi gas when the system is dilute enough so that the positive helicity branch is not occupied at all in the non-interacting ground state. We show that the theory is renormalizable in perturbation theory and therefore yields a model of polarized fermions that avoids a multi-channel treatment of the problem. Our results open the path towards a much more straightforward approach to the many-body physics of cold atoms subject to artificial vector potentials.