title: Finite-temperature collective dynamics of a Fermi gas in the BEC-BCS crossover.
abstract: We report on experimental studies on the collective behavior of a strongly interacting Fermi gas with tunable interactions and variable temperature. A scissors mode excitation in an elliptical trap is used to characterize the dynamics of the quantum gas in terms of hydrodynamic or near-collisionless behavior. We obtain a crossover phase diagram for collisional properties, showing a large region where a nonsuperfluid strongly interacting gas shows hydrodynamic behavior. In a narrow interaction regime on the BCS side of the crossover, we find a novel temperature-dependent damping peak, suggesting a relation to the superfluid phase transition.
authors.affiliation: Institut für Experimentalphysik und Forschungszentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria.
authors.forename: M J
authors.initials: MJ
authors.lastname: Wright
authors.forename: S
authors.initials: S
authors.lastname: Riedl
authors.forename: A
authors.initials: A
authors.lastname: Altmeyer
authors.forename: C
authors.initials: C
authors.lastname: Kohstall
authors.forename: E R Sánchez
authors.initials: ER
authors.lastname: Guajardo
authors.forename: J Hecker
authors.initials: JH
authors.lastname: Denschlag
authors.forename: R
authors.initials: R
authors.lastname: Grimm