Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS Crossover

Understand

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 non-superfluid 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.