Critical spin transport in Bose gases

TL;DR

This paper investigates how spin transport in a three-dimensional two-component Bose gas near the critical temperature is governed by critical phenomena, revealing deviations from classical models due to phase transition effects.

Contribution

It demonstrates that spin conductivity near the critical temperature is dictated by critical exponents, differing from Boltzmann predictions, and discusses experimental observability.

Findings

Spin conductivity deviates from Boltzmann predictions near criticality.

Critical exponents determine the temperature dependence of spin transport.

The critical region size for experimental observation is analyzed.

Abstract

We consider spin transport in a two-component atomic Bose gas in three dimensions, at temperatures just above the critical temperature for Bose-Einstein condensation. In these systems the spin conductivity is determined by spin drag, i.e., frictional drag between the two spin components due to interactions. We find that in the critical region the temperature dependence of the spin conductivity deviates qualitatively from the Boltzmann result and is fully determined by the critical exponents of the phase transition. We discuss the size of the critical region where these results may be observed experimentally.