Sarma Phase in Trapped Unbalanced Fermi Gases

TL;DR

This paper investigates the stability and phase boundaries of the Sarma superfluid phase in trapped unbalanced Fermi gases at nonzero temperatures, explaining recent experimental observations and resolving apparent contradictions.

Contribution

It provides a detailed analysis of the phase diagram of unbalanced Fermi gases, emphasizing the role of the Sarma phase in experimental results.

Findings

Sarma phase is stable in trapped unbalanced Fermi gases at finite temperature.

Phase boundaries between superfluid, normal, and phase-separated states are mapped.

The physics of the Sarma phase explains recent experimental observations.

Abstract

We consider a trapped unbalanced Fermi gas at nonzero temperatures where the superfluid Sarma phase is stable. We determine in particular the phase boundaries between the superfluid, normal, and phase separated regions of the trapped unbalanced Fermi mixture. We show that the physics of the Sarma phase is sufficient to understand the recent observations of Zwierlein et al. [Science 311, 492 (2006); Nature 442, 54 (2006)] and indicate how the apparent contradictions between this experiment and the experiment of Partridge et al. [Science 311, 503 (2006)] may be resolved.