Superfluid Boson–Fermion Mixture: Structure Formation and Collective Periodic Motion

Abstract

Multiple periodic domain formation due to a modulation instability in a boson–fermion mixture superfluid in the unitary regime has been studied. The periodicity of the structure evolves with time. At the early stage of evolution, bosonic domains show the periodic nature, whereas the periodicity in the fermionic (Cooper pair) domains appears at the late stage of evolution. The nature of interatomic interspecies interactions affects the domain formation. In a harmonic trap, the mixture executes an undamped oscillation. The frequency of the oscillation depends on the relative coupling strength between boson–fermion and fermion–fermion. The repulsive boson–fermion interaction reduces the oscillation frequency, whereas the attractive interaction enhances the frequency significantly.