Longitudinal spin diffusion in a nondegenerate trapped $^{87}$Rb gas

TL;DR

This study investigates how coherence affects longitudinal spin diffusion in a nondegenerate trapped $^{87}$Rb gas, revealing slower diffusion, altered oscillation frequencies, and spin conversion phenomena.

Contribution

It demonstrates the impact of coherence on spin diffusion dynamics and uncovers spin coupling instabilities in a nondegenerate atomic gas.

Findings

Coherence slows down longitudinal spin diffusion.

Spin coupling causes oscillation frequency changes.

Conversion of longitudinal to transverse spin increases coherence.

Abstract

Longitudinal spin diffusion of two pseudo-spin domains is studied in a trapped $^{87}$Rb sample above quantum degeneracy, and the effect of coherence in the domain wall on the dynamics of the system is investigated. Coherence in a domain wall leads to transverse-spin-mediated longitudinal spin diffusion that is slower than classical predictions, as well as altering the domains' oscillation frequency. The system also shows an instability in the longitudinal spin dynamics as longitudinal and transverse spin components couple, and a conversion of longitudinal spin to transverse spin is observed, resulting in an increase in the total amount of coherence in the system.