title: Phonon spectrum and dynamical stability of a dilute quantum degenerate Bose-Fermi mixture.
abstract: We calculate the phonon excitation spectrum in a zero-temperature dilute boson-fermion gaseous mixture. We show how the sound velocity changes due to the boson-fermion interaction, and we determine the dynamical stability regime of a homogeneous mixture. We identify a resonant phonon-exchange interaction between the fermions as the physical mechanism leading to the instability.
authors.affiliation: Optical Sciences Center, The University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Han
authors.initials: H
authors.lastname: Pu
authors.forename: Weiping
authors.initials: W
authors.lastname: Zhang
authors.forename: Martin
authors.initials: M
authors.lastname: Wilkens
authors.forename: Pierre
authors.initials: P
authors.lastname: Meystre