Spin-Seebeck effect in a strongly interacting Fermi gas

TL;DR

This paper investigates the spin-Seebeck effect in a strongly interacting Fermi gas, proposing an experiment to measure it and analyzing how the effect varies with temperature and interaction strength, including a sign change in the spin-Seebeck coefficient.

Contribution

It introduces a theoretical framework for the spin-Seebeck effect in strongly interacting Fermi gases and predicts a sign change of the effect with temperature and interaction parameters.

Findings

Spin-Seebeck coefficient changes sign with temperature.

Zero-crossing temperature depends on interaction strength.

Sign reversal occurs in the unitary limit.

Abstract

We study the spin-Seebeck effect in a strongly interacting, two-component Fermi gas and propose an experiment to measure this effect by relatively displacing spin up and spin down atomic clouds in a trap using spin-dependent temperature gradients. We compute the spin-Seebeck coefficient and related spin-heat transport coefficients as functions of temperature and interaction strength. We find that when the inter-spin scattering length becomes larger than the Fermi wavelength, the spin-Seebeck coefficient changes sign as a function of temperature, and hence so does the direction of the spin-separation. We compute this zero-crossing temperature as a function of interaction strength and in particular in the unitary limit for the inter-spin scattering.