Density profiles of polarized Fermi gases confined in harmonic traps

TL;DR

This paper calculates density profiles of polarized Fermi gases in harmonic traps at zero temperature, revealing phase transitions and comparing theoretical results with experimental measurements.

Contribution

It introduces a method to analyze phase transitions in trapped polarized Fermi gases using the local density approximation based on the uniform system phase diagram.

Findings

Discontinuity in density profiles indicates a first order phase transition.

Profiles depend on polarization and interaction strength.

Quantitative agreement with experimental measurements.

Abstract

On the basis of the phase diagram of the uniform system we calculate the density profiles of a trapped polarized Fermi gas at zero temperature using the local density approximation. By varying the overall polarization and the interaction strength we analyze the appearance of a discontinuity in the profile, signalling a first order phase transition from a superfluid inner core to a normal outer shell. The local population imbalance between the two components and the size of the various regions of the cloud corresponding to different phases are also discussed. The calculated profiles are quantitatively compared with the ones recently measured by Shin {\it et al.}, Phys. Rev. Lett. {\bf 101}, 070404 (2008).