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Experimental Studies of Fermionic Lithium in the BEC-BCS Crossover

ABSTRACT: We discuss recent experiments performed on ultra-cold gases of fermionic 6Li in a crossed-beam optical trap.  This system enables the investigation of the so-called BEC-BCS cross-over region.  Using a Feshbach resonance, the magnitude of the atomic interactions can be tuned between the strongly interacting regime, where the ground state is a Bose-Einstein condensate (BEC) of molecules, to the weakly interacting regime, where the BCS (Bardeen-Cooper-Schrieffer) theory of superconductivity is more appropriate.  We have investigated the momentum distribution of the gas as well as its anisotropic expansion in the presence of interactions.  In addition, we have studied the possibility of breaking pairs of atoms by modulating the trap strength.  I will also describe a currently evolving reconstruction and upgrade of the apparatus and our outlook for experiments in the near future.