Bound State of Ultracold Fermions in the Spin Imbalanced Normal State

F. Fumarola; I. L. Aleiner; B. L. Altshuler

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Bound State of Ultracold Fermions in the Spin Imbalanced Normal State

F. Fumarola·I. L. Aleiner·B. L. Altshuler

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Abstract

We study a polarized Fermi gas and demonstrate that Fano-Feshbach (FF) resonances lead to the pairing of fermions and holes into long living massive bosonic modes (bifermions and biholes), which can be viewed as signatures of a first order quantum phase transition. These modes, which are neither conventional Cooper pairs nor closed channel bosonic dimers, have a peculiar dispersion relation and appear already in the weak coupling limit, i.e. for large FF detunings. Our result is in accord with claims of Schunck \emph{et al.} [cond-mat/0702066] that by stabilizing the normal state the population imbalance still allows effect of s-wave fermionic pairing.

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F. Fumarola, I. L. Aleiner, B. L. Altshuler. 2007-03-02. Bound State of Ultracold Fermions in the Spin Imbalanced Normal State. https://arxiv.org/abs/cond-mat/0703003

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