RPA study of collective excitations in the Bose–Fermi mixed atomic gases with large excess of bosons

Abstract

We study collective excitations in the Bose–Fermi mixed condensate of atomic gases with large excess of bosons based on the self-consistent Hartree–Fock and Random Phase Approximation. We investigate response of the system to a monopole type external field, and find that the fermionic strength is concentrated in a single collective state for a repulsive boson–fermion interaction. The dynamical structure factor for this state shows that fermions are correlated through the Bose condensate.