Metastability in Spin-Polarized Fermi Gases

TL;DR

This paper investigates how particle transport and evaporation influence phase separation in ultracold spin-polarized Fermi gases, revealing metastable deformations caused by nonequilibrium effects at the phase boundary.

Contribution

It demonstrates that evaporative depolarization and inhibited spin transport lead to metastable deformations in the superfluid core of spin-polarized Fermi gases.

Findings

Deformation of superfluid core due to evaporative depolarization

Metastability of deformed state lasting up to 2 seconds

Nonequilibrium chemical potential jumps at phase boundary

Abstract

We study the role of particle transport and evaporation on the phase separation of an ultracold, spin-polarized atomic Fermi gas. We show that the previously observed deformation of the superfluid paired core is a result of evaporative depolarization of the superfluid due to a combination of enhanced evaporation at the center of the trap and the inhibition of spin transport at the normal-superfluid phase boundary. These factors contribute to a nonequilibrium jump in the chemical potentials at the phase boundary. Once formed, the deformed state is highly metastable, persisting for times of up to 2 s.