Expansion of a lithium gas in the BEC-BCS crossover

J. Zhang (1) , E.G.M. van Kempen (2) , Thomas Bourdel (3) , L. Khaykovich (4) , J. Cubizolles (3) , F. Chevy (3) , M. Teichmann (3) , L. Tarruell (3) , S.J.J.M.F. Kokkelmans (2) , C. Salomon (3)

1 SKLQOQOD
2 TU/e - Eindhoven University of Technology [Eindhoven]
3 LKB (Lhomond) - Laboratoire Kastler Brossel
4 Department of Physics

We report on experiments in $^6$Li Fermi gases near Feshbach resonances. A broad $s$-wave resonance is used to form a Bose-Einstein condensate of weakly bound $^6$Li$_2$ molecules in a crossed optical trap. The measured molecule-molecule scattering length of $170^{+100}_{-60}$\,nm at 770\,G is found in good agreement with theory. The expansion energy of the cloud in the BEC-BCS crossover region is measured. Finally we discuss the properties of $p$-wave Feshbach resonances observed near 200\,Gauss and new $s$-wave resonances in the heteronuclear $^6$Li- $^7$Li mixture.

Mots clés: Cold atoms; Cold molecules; BEC-BCS cross-over

Domaines: Mécanique statistique [cond-mat.stat-mech]

J. Zhang, E.G.M. van Kempen, Thomas Bourdel, L. Khaykovich, J. Cubizolles, et al.. Expansion of a lithium gas in the BEC-BCS crossover. 2004. ⟨hal-00003019⟩