Excitation properties and effects of mass imbalance in the BCS-BEC crossover regime of an ultracold Fermi gas

Ryo Hanai, Takashi Kashimura, Ryota Watanabe, Daisuke Inotani, Yoji Ohashi

研究成果: Article査読

21 被引用数 (Scopus)

抄録

We investigate single-particle properties of a mass-imbalanced Fermi gas in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover region. In the presence of mass imbalance, we point out that the ordinary T-matrix approximation, which has been extensively used to clarify various BCS-BEC crossover physics in the mass-balanced case, unphysically gives a double-valued solution in terms of the superfluid phase transition temperature Tc in the crossover region. To overcome this serious problem, we include higher order strong-coupling corrections beyond the T-matrix level. Using this extended T-matrix theory, we calculate single-particle excitations in the normal state above Tc. The so-called pseudogap phenomena originating from pairing fluctuations are shown to be different between the light-mass component and heavy-mass component, which becomes more remarkable at higher temperatures. Since Fermi condensates with hetero-Cooper pairs have recently been discussed in various fields, such as exciton (polariton) condensates as well as color superconductivity, our results would be useful for the further development of Fermi superfluid physics, beyond the conventional superfluid state with homo-Cooper pairs.

本文言語English
論文番号053621
ジャーナルPhysical Review A - Atomic, Molecular, and Optical Physics
88
5
DOI
出版ステータスPublished - 2013 11月 18

ASJC Scopus subject areas

  • 原子分子物理学および光学

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