Diversified vortex phase diagram for a rotating trapped two-band Fermi gas in the BCS-BEC crossover

Abstract

We report the equilibrium vortex phase diagram of a rotating two-band Fermi gas confined to a cylindrically symmetric parabolic trapping potential, using the recently developed finite-temperature effective field theory [Phys. Rev. A $\bf{94}$, 023620 (2016)]. A non-monotonic resonant dependence of the free energy as a function of the temperature and the rotation frequency is revealed for a two-band superfluid. We particularly focus on novel features that appear as a result of interband interactions and can be experimentally resolved. The resonant dependence of the free energy is directly manifested in vortex phase diagrams, where areas of stability for both integer and fractional vortex states are found. The study embraces the BCS-BEC crossover regime and the entire temperature range below the critical temperature $T_{c}$. Significantly different behavior of vortex matter as a function of the interband coupling is revealed in the BCS and BEC regimes.