Quadrupole oscillation in a dipolar Fermi gas: Hydrodynamic versus collisionless regime

Year: 2012

Authors: Abad M., Recati A., Stringari S.

Autors Affiliation: Departament d\’Estructura i Constituents de la Matèria, and Facultat de Física, Universitat de Barcelona, E-08028 Barcelona, Spain; INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, I-38123 Povo, Italy

Abstract: The surface quadrupole mode of an harmonically trapped dipolar Fermi gas is studied in both the hydrodynamic and collisionless regimes. The anisotropy and long-range effects of the dipolar force as well as the role of the trapping geometry are explicitly investigated. In the hydrodynamic regime the frequency is always slightly smaller than the root 2 omega(perpendicular to) value holding for gases interacting with contact interactions. In the collisionless regime the frequency can be either pretty smaller or larger than the noninteracting value 2 omega(perpendicular to), depending on the cloud aspect ratio. Our results suggest that the frequency of the surface quadrupole oscillation can provide a useful test for studying, at very low temperatures, the transition between the normal and the superfluid phase and, in the normal phase at higher temperatures, the crossover between the collisional and collisionless regimes. The consequences of the anisotropy of the dipolar force on the virial theorem are also discussed.


Volume: 85 (3)      Pages from: 033639  to: 033639

More Information: We acknowledge P. Pedri for stimulating discussions. Useful discussions with S. Giovanazzi, M. Klawunn, N. Matveeva, and C. Menotti are also acknowledged. This work has been supported by the European Research Council through the QGBE grant. M.A. was supported by Comissionat per a Universitats i Recerca del Departament d\’Innovacio, Universitats i Empresa (Generalitat de Catalunya), and the European Social Fund. M.A. thanks the group at the BEC center and the University of Trento for their kind hospitality and nice discussions.
KeyWords: dipolar gases; collective modes; collective excitations
DOI: 10.1103/PhysRevA.85.033639

Citations: 6
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