Phys. Rev. Lett. 92, 203201 (2004) [4 pages]Collective Excitations of a Degenerate Gas at the BEC-BCS CrossoverReceived 29 March 2004; published 19 May 2004 We study collective excitation modes of a fermionic gas of 6Li atoms in the BEC-BCS crossover regime. While measurements of the axial compression mode in the cigar-shaped trap close to a Feshbach resonance confirm theoretical expectations, the radial compression mode shows surprising features. In the strongly interacting molecular BEC regime, we observe a negative frequency shift with increasing coupling strength. In the regime of a strongly interacting Fermi gas, an abrupt change in the collective excitation frequency occurs, which may be a signature for a transition from a superfluid to a collisionless phase. © 2004 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.92.203201
DOI:
10.1103/PhysRevLett.92.203201
PACS:
34.50.–s, 05.30.Fk, 32.80.Pj, 39.25.+k
See AlsoComment: R. Combescot and X. Leyronas, Comment on “Collective Excitations of a Degenerate Gas at the BEC-BCS Crossover”, Phys. Rev. Lett. 93, 138901 (2004). |
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