p-wave pairing in a two-component Fermi system with unequal population: Weak-coupling BCS to strong-coupling BEC regimes

Article

关键词: PHASE-TRANSITION;    SUPERCONDUCTIVITY;    GAS;    FERROMAGNETISM;    SUPERFLUIDITY;    CONDENSATION;    COEXISTENCE;    ATOMS;   

DOI  :  10.1103/PhysRevB.88.134507

来源: SCIE

【 摘 要 】

We study p-wave pairing in a two-component Fermi system with unequal population across weak-coupling BCS to strong-coupling BEC regimes. We find a rich m(s) = 0 spin triplet p-wave superfluid (SF) ground state (GS) structure as a function of population imbalance. Under a phase stability condition, the global energy minimum is given by a multitude of mixed SF states formed of linear combinations of m = +/- 1,0 substates of the l = 1 orbital angular momentum state. Except for the pure SF states (l = 1, m = +/- 1), other states exhibit oscillation in energy with the relative phase between the constituent gap amplitudes. We also find states with local energy minimum that can be stable at higher polarizations, suggesting a quantum phase transition between the global and local minima phases driven by polarization. We relate the local and global minimum states to Morse and non-Morse critical points. We calculate the variations of the ground state energy with a relative phase angle, coupling, and polarization, and discuss possible consequences for experiments.

【 授权许可】

Free