Abstract
We report on the expansion of an ultracold Fermi-Fermi mixture of and under conditions of strong interactions controlled via an interspecies Feshbach resonance. We study the expansion of the mixture after release from the trap and, in a narrow magnetic-field range, we observe two phenomena related to hydrodynamic behavior. The common inversion of the aspect ratio is found to be accompanied by a collective effect where both species stick together and expand jointly despite of their widely different masses. Our work constitutes a major experimental step for a controlled investigation of the many-body physics of this novel strongly interacting quantum system.
- Received 23 November 2010
DOI:https://doi.org/10.1103/PhysRevLett.106.115304
© 2011 American Physical Society