Spin-drag relaxation time in one-dimensional spin-polarized Fermi gases

URL:http://link.aps.org/doi/10.1103/PhysRevB.77.035113 DOI:10.1103/PhysRevB.77.035113Spin propagation in systems of one- dimensional interacting fermions at finite temperature is intrinsically diffusive. The spreading rate of a spin packet is controlled by a transport coefficient termed “spin drag” relaxation time τsd. In this paper we present both numerical and analytical calculations of τsd for a two-component spin-polarized cold Fermi gas trapped inside a tight atomic waveguide. At low temperatures we find an activation law for τsd, in agreement with earlier calculations of Coulomb drag between slightly asymmetric quantum wires, but with a different and much stronger temperature dependence of the prefactor. Our results provide a fundamental input for microscopic time-dependent spin-density functional theory calculations of spin transport in one-dimensional inhomogeneous systems of interacting fermions.M.P. thanks Michael Köhl for helpful discussions, and M.P.T. acknowledges the hospitality of the Condensed Matter and Statistical Physics group of the Abdus Salam International Centre for Theoretical Physics in Trieste.We wish to thank Michael Pustilnik and Leonid Glazman for useful correspondence. G.V. was supported by DOE Grant No. DEFG02-05ER46203