https://doi.org/10.1140/epjd/e2015-60131-7
Regular Article
Collective modes of p-wave superfluid Fermi gases in BEC phase
1 Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, and Istituto Nazionale di Fisica Nucleare, Sezione di Firenze Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
2 Frankfurt University of Applied Sciences, Nibelungenplatz 1, 60318 Frankfurt am Main, Germany
a
e-mail: matera@fi.infn.it
b
e-mail: mfwagner@mailaps.org
Received: 26 February 2015
Received in final form: 25 May 2015
Published online: 16 June 2015
The low-energy modes of a superfluid atomic Fermi gas at zero temperature are investigated. The Bose-Einstein-condensate (BEC) side of the superfluid phase is studied in detail. The atoms are assumed to be in only one internal state, so that for a sufficiently diluted gas the pairing of fermions can be considered effective in the l = 1 channel only. In agreement with previous works on p-wave superfluidity in Fermi systems, it is found that the px + ipy phase represents the lowest energy state in both the Bardeen-Cooper-Schrieffer (BCS) and BEC sides. Our calculations show that at low energy three branches of collective modes can emerge, with different species of dispersion relations: a phonon-like mode, a single-particle-like mode and a gapped mode. A comparison with the Bogoliubov excitations of the corresponding spinor Bose condensate is made. They reproduce the dispersion relations of the excitation modes of the p-wave superfluid Fermi gas to a high accuracy.
Key words: Cold Matter and Quantum Gas
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2015