Absence of BCS Condensation of Atoms in a Repulsive Fermi Gas of Atoms

Possible Bose-Einstein condensation of molecules and Bardeen-Cooper-Schrieffer (BCS) condensation of Cooper pairs of atoms in an ultracold Fermi gas of atoms with a repulsive two-body interaction are studied by using the path integral representation of the grand partition function. From the self-con...

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Bibliographic Details
Published inarXiv.org
Main Authors Han, Fuxiang, Li, Hailing, Minghao Lei, E Wu
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 11.10.2005
Subjects
Condensation
Cooper pairs
Helium
Mathematical analysis
Order parameters
Partitions (mathematics)
Quantum theory
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Summary:Possible Bose-Einstein condensation of molecules and Bardeen-Cooper-Schrieffer (BCS) condensation of Cooper pairs of atoms in an ultracold Fermi gas of atoms with a repulsive two-body interaction are studied by using the path integral representation of the grand partition function. From the self-consistent equations obtained in the present work for the order parameters, we have found that BCS condensation of atoms can't occur in such a Fermi gas of atoms and that the condensate observed experimentally is composed of condensed molecules or possibly of preformed Cooper pairs. To substantiate our conclusions from the self-consistent equations for the order parameters, the effective atom-atom interaction mediated through molecules has also been computed with the Foldy-Wouthuysen transformation and has been found to be repulsive, which implies a net repulsive two-body interaction between atoms and hence the absence of BCS condensation of atoms.
ISSN:2331-8422