Experimental Study of the BEC-BCS Crossover Region in Lithium 6

Abstract

We report Bose-Einstein condensation of weakly bound ${}^6$Li${}_2$molecules in a crossed optical trap near a Feshbach resonance. We measure a molecule-molecule scattering length of$170_{-60}^{+100}$ nm at 770 G, in good agreement with theory.We study the expansion of the cloud in the BEC-BCS crossoverregion.

4 pages, 3 figures, submitted to PRL