The normal phase of an imbalanced Fermi gas

TL;DR

This paper develops a simple theoretical model for the normal phase of an imbalanced Fermi gas, focusing on Fermi polarons and their interactions, highlighting the role of the Pauli exclusion principle.

Contribution

It provides an exact formula for polaron interactions in an imbalanced Fermi gas, linking them to a single polaron parameter and the Pauli exclusion principle.

Findings

Derived an exact interaction formula between polarons

Identified the interaction as a signature of Pauli exclusion

Applicable to dilute Fermi-polaron ensembles

Abstract

Recent experiments on imbalanced Fermi gases have raised interest in the physics of an impurity immersed in a Fermi sea, the so-called Fermi polaron. In this letter, a simple theory is devised to describe dilute Fermi-polaron ensembles corresponding to the normal phase of an imbalanced Fermi gas. An exact formula is obtained for the dominant interaction between polarons, expressed solely in terms of a single polaron parameter. The physics of this interaction is identified as a signature of the Pauli exclusion principle.