Superfluidity in Ultracold Fermi Gases: From Bose-Einstein Condensation of Molecules to Cooper Pairs
Prof. Christophe Salomon, Directeur de Recherche au CNRS (Laboratoire Kastler Brossel, ENS Paris, France)

We will describe recent experiments studying superfluidity in dilute ultra-cold Fermi gases. Thanks to a resonance phenomenon in cold collisions, it is possible to adjust the sign and magnitude of the effective interaction between trapped fermions and to enter into the strongly correlated regime. Taking advantage of this tunability of interactions, it has been possible to produce Bose-Einstein condensates (BEC) of molecules and to study some of their properties.
These composite bosonic molecules possess a remarkable stability with respect to inelatsic vibrational decay. We show that this phenomenon is a consequence of the Pauli exclusion principle acting on the fermion pairs.

We will then present recent data recorded in the crossover region between BEC of molecules and the BCS regime of fermions with weak attractive interaction. The unitary limit reached on resonance is a particularly interesting regime because of its universal character.

Finally a few perspectives for this new field of "condensed matter with ultracold atoms and light "will be given. In particular, atoms confined in periodic potentials created by light offers the possibility to address some key issues of the quantum many-body physics of interacting particles in 1, 2 and 3 dimensions.