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arXiv · 1207.2580

Superfluid phase transition and strong-coupling effects in an ultracold Fermi gas with mass imbalance

Ryo Hanai·Takashi Kashimura·Ryota Watanabe·Daisuke Inotani·Yoji Ohashi
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Abstract

We investigate the superfluid phase transition and effects of mass imbalance in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover regime of an cold Fermi gas. We point out that the Gaussian fluctuation theory developed by Nozières and Schmitt-Rink and the $T$-matrix theory, that are now widely used to study strong-coupling physics of cold Fermi gases, give unphysical results in the presence of mass imbalance. To overcome this problem, we extend the $T$-matrix theory to include higher-order pairing fluctuations. Using this, we examine how the mass imbalance affects the superfluid phase transition. Since the mass imbalance is an important key in various Fermi superfluids, such as $^{40}$K-$^6$Li Fermi gas mixture, exciton condensate, and color superconductivity in a dense quark matter, our results would be useful for the study of these recently developing superfluid systems.

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Ryo Hanai, Takashi Kashimura, Ryota Watanabe, Daisuke Inotani, Yoji Ohashi. 2012-07-11. Superfluid phase transition and strong-coupling effects in an ultracold Fermi gas with mass imbalance. https://doi.org/10.1007/s10909-012-0738-9

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