Anomalous Spin segregation in a weakly interacting two-component Fermi gas

TL;DR

This paper explains observed spin segregation in a two-component Fermi gas as a mean-field effect, using a collisionless Boltzmann equation, highlighting how small potential differences and interactions create long-lived spin textures.

Contribution

It introduces a collisionless Boltzmann equation approach to model spin segregation, emphasizing the role of mean-field interactions in a weakly interacting Fermi gas.

Findings

Close agreement with experimental spin dynamics data

Interaction strength influences spin texture development

Small potential differences drive initial spin currents

Abstract

We explain the spin segregation seen at Duke in a two-component gas of 6Li [Du, Luo, Clancy and Thomas, Phys. Rev. Lett. 101,150401 (2008)] as a mean-field effect describable via a collisionless Boltzmann equation. As seen in experiments, we find that slight differences in the trapping potentials in the two spin states drive small spin currents. Hartree-Fock type interactions convert these currents into a redistribution of populations in energy space, and consequently a long lived spin texture develops. We explore the interaction strength dependence of these dynamics, finding close agreement with experiment.