title: Superfluid expansion of a rotating Fermi gas.
abstract: We study the expansion of a rotating, superfluid Fermi gas. The presence and absence of vortices in the rotating gas are used to distinguish the superfluid and normal parts of the expanding cloud. We find that the superfluid pairs survive during the expansion until the density decreases below a critical value. Our observation of superfluid flow in the expanding gas at 1/kFa=0 extends the range where fermionic superfluidity has been studied to densities of 1.2x10(11) cm(-3), about an order of magnitude lower than any previous study.
authors.affiliation: Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, MIT, Cambridge, Massachusetts 02139, USA.
authors.forename: C H
authors.initials: CH
authors.lastname: Schunck
authors.forename: M W
authors.initials: MW
authors.lastname: Zwierlein
authors.forename: A
authors.initials: A
authors.lastname: Schirotzek
authors.forename: W
authors.initials: W
authors.lastname: Ketterle