The Nature of Superfluidity in Ultracold Fermi Gases Near Feshbach Resonances

We study the ``resonant'' superfluid state of atomic Fermi gases using a BCS-BEC crossover theory which includes ``pseudogap'' effects. This pseudogap reflects pre-formed pairs of two varieties (Cooper-pair-like and molecular bosons), present at and above $T_c$ which are associated with a normal state excitation gap. These non-condensed bosons persist below $T_c$, leading to non-BCS characteristics. We discuss the signatures of the onset of superfluidity and how they differ from conventional expectations.