Abstract. The zero-temperature properties of a dilute two-component Fermi gas in the Bardeen–Cooper–Schrieffer phase–Bose–Einstein condensate crossover are investigated. On the basis of a generalization of the variational Schwinger method, we construct approximate semi-analytical formulae for collective frequencies of the radial and the axial breathing modes of the Fermi gas under harmonic confinement in the framework of the hydrodynamic theory. It is shown that the method gives nearly exact solutions.

Print publication: Issue 14 (28 July 2005)
Received 9 May 2005, in final form 9 June 2005
Published 4 July 2005