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arXiv · 0811.1615

Casimir interaction among heavy fermions in the BCS-BEC crossover

Yusuke Nishida
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Abstract

We investigate a two-species Fermi gas with a large mass ratio interacting by an interspecies short-range interaction. Using the Born-Oppenheimer approximation, we determine the interaction energy of two heavy fermions immersed in the Fermi sea of light fermions as a function of the s-wave scattering length. In the BCS limit, we recover the perturbative calculation of the effective interaction between heavy fermions. The p-wave projection of the effective interaction is attractive in the BCS limit while it turns out to be repulsive near the unitarity limit. We find that the p-wave attraction reaches its maximum between the BCS and unitarity limits, where the maximal p-wave pairing of heavy minority fermions is expected. We also investigate the case where the heavy fermions are confined in two dimensions and the p-wave attraction between them is found to be stronger than that in three dimensions.

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Yusuke Nishida. 2009-01-29. Casimir interaction among heavy fermions in the BCS-BEC crossover. https://doi.org/10.1103/physreva.79.013629

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