Competition between Bose Einstein Condensation and spin dynamics

B Naylor (1) , M Brewczyk (2) , M Gajda (3, 4) , Olivier Gorceix (1) , E Maréchal (1) , L Vernac (1) , B Laburthe-Tolra (1)

1 LPL - Laboratoire de Physique des Lasers
2 Wydziaa l Fizyki, Uniwersytet w Bialymstoku
3 Instytut Fizyki PAN
4 WMP-SN

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.

Mots clés: spin fluctuations; Bose-Einstein condensate; spin dynamics; spinor; Out-of-equilibrium condensates

Domaines: Physique Atomique [physics.atom-ph]; Physique Quantique [quant-ph]; Matière Condensée [cond-mat]

B Naylor, M Brewczyk, M Gajda, Olivier Gorceix, E Maréchal, et al.. Competition between Bose Einstein Condensation and spin dynamics. Physical Review Letters, 2016, 117, pp.185302. ⟨10.1103/PhysRevLett.117.185302⟩. ⟨hal-01347485⟩