Competition between Bose Einstein Condensation and spin dynamics

TL;DR

This paper investigates how spin-exchange collisions influence Bose-Einstein condensation in a chromium gas, revealing that condensation occurs before full spin thermalization, affecting spin dynamics and resulting in metastable spinor condensates.

Contribution

It demonstrates the interplay between Bose-Einstein condensation and spin dynamics, highlighting the timing of condensation relative to spin thermalization in a multi-component gas.

Findings

Condensation occurs before full spin thermalization.

Spin dynamics are triggered by increased density after condensation.

Metastable spinor condensates with strong spin fluctuations are observed.

Abstract

We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation, by rapidly cooling a chromium multi-component Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin-degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin excited states. Small metastable spinor condensates are nevertheless produced, and manifest strong spin fluctuations.