Comment on "Normal phase of an imbalanced Fermi gas"

TL;DR

This paper clarifies that the quadratic energy term in an imbalanced Fermi gas can be understood as resulting from interactions among minority atoms mediated by the majority component, rather than solely from Pauli blocking effects.

Contribution

It provides an alternative interpretation of the quadratic energy contribution, linking it to induced interactions among minority atoms in an imbalanced Fermi gas.

Findings

Quadratic energy term can be explained by induced interactions.

Clarifies the physical origin of the E^(2) term.

Supports the interpretation with theoretical analysis.

Abstract

Recently Mora and Chevy [Phys. Rev. Lett. 104, 230402 (2010), arXiv:1003.0213v2], in studying the energy of an atomic Fermi gas consisting of a majority species, 1, and a minority species, 2, showed that, due to interatomic interactions, the energy density E of the gas has a contribution of the form E^(2)= f n_2^2 /2, where n_i is the density of species i. They attribute this term to a `modification of the single polaron properties due to Pauli blocking'. In this Comment, we demonstrate that E^(2) may equivalently be understood in terms of the familiar interaction between minority atoms induced by the majority component.