Condensation of Fermions in the double-well potential

The density distribution of ultracold two-component fermionic gases ⁶Li, which are confined in a gradient magnetic field and a symmetrical double-well potential, is investigated by employing local-density approximation. It is found that three different regimes including quasi-molecular Bose–Einstein condensation (BEC_m), the dimers in the unitarity limit (UL_d), and Bardeen–Cooper–Schrieffer superfluid (BCS) can coexist at the same time. Furthermore, the ranges of these regimes can be controlled to some extent by tuning the gradient of the magnetic field and the parameters characterizing the properties of the double-well potential. This study is of guidance and significance for experimentally realizing the coexistence of BEC_m, UL_d, and BCS in the double-well potential.