Inhomogeneous spin diffusion in traps with cold atoms

TL;DR

This paper investigates how inhomogeneous spin diffusion occurs in cold atom traps, revealing how density-dependent diffusion affects spin flow and oscillations across temperature ranges, aligning with some experimental results.

Contribution

It introduces a detailed analysis of inhomogeneous spin diffusion in cold atom traps, emphasizing the impact of density dependence and trap size on spin dynamics.

Findings

Inhomogeneous spin diffusion varies from center to surface with temperature.

Finite trap size reduces spin diffusion rates at low temperatures.

Results align with experimental data for resonant attractive interactions.

Abstract

The spin diffusion and damped oscillations are studied in the collision of two spin polarized clouds of cold atoms with resonant interactions. The strong density dependence of the diffusion coefficient leads to inhomogeneous spin diffusion that changes from central to surface spin flow as the temperature increases. The inhomogeneity and the smaller finite trap size significantly reduce the spin diffusion rate at low temperatures. The resulting spin diffusion rates, spin drag and initial damped oscillations are compatible with measurements at low to high temperatures for resonant attractive interactions but are incompatible with a metastable ferromagnetic phase.