BCS excitations in a superfluid gas of trapped Fermi atoms

Degenerate atomic Fermi gases can exhibit both the BCS phase found in superconductors as well as a superfluid phase involving a BEC of molecules. In the last year, this BCS-BEC crossover has been studied in ultracold atomic Fermi gases, using Feshbach resonances to increase the strength of the attractive interaction between trapped Fermi atoms. In this review talk, I will show how the BCS quasiparticle states in a Fermi superfluid change as we go from the BCS weak-coupling region involving Cooper pairs to the BEC strong-coupling region involving molecules. I will also briefly discuss recent tunneling experiments used to measure the single-particle excitations and the pairing gap.