Elastic theory of Normal-Superfluid Boundary in trapped Fermi Gases

TL;DR

This paper models the normal-superfluid boundary in trapped polarized Fermi gases as an elastic membrane, revealing shape distortions influenced by trap anisotropy and providing an analytic explanation for these phenomena.

Contribution

It introduces an elastic membrane model for the boundary, offering new insights into shape distortions in polarized Fermi gases under various trap geometries.

Findings

Boundary remains elliptical at low anisotropy

Boundary becomes capsule-shaped in prolate traps

Analytic explanation for boundary shape provided

Abstract

By modeling the normal-superfluid boundary in a trapped polarized Fermi gas as an elastic membrane, we calculate the atomic density profile. For small trapping anisotropy, we find that the superfluid-normal boundary remains approximately elliptical, and has an aspect ratio different from that of the trap. For very prolate clouds the boundary becomes distorted into a capsule-like shape. We present an analytic explanation of this shape.