Renormalization Group Theory for the Imbalanced Fermi Gas

TL;DR

This paper develops a renormalization group framework for imbalanced Fermi gases, accurately capturing phase transition behavior and aligning well with recent experimental findings.

Contribution

It introduces a Wilsonian renormalization group approach tailored for imbalanced Fermi gases, providing quantitative predictions across coupling regimes.

Findings

Identifies the line of second-order phase transitions.

Locates the tricritical point.

Shows good agreement with experimental data.

Abstract

We formulate a wilsonian renormalization group theory for the imbalanced Fermi gas. The theory is able to recover quantitatively well-established results in both the weak-coupling and the strong-coupling (unitarity) limit. We determine for the latter case the line of second-order phase transitions of the imbalanced Fermi gas and in particular the location of the tricritical point. We obtain good agreement with the recent experiments of Y. Shin {\it et al}. [Nature {\bf 451}, 689 (2008)].