  In this paper we describe a scheme for state transfer between a trapped
atomic Bose condensate and an optomechanical end-mirror mediated by a cavity
field. Coupling between the mirror and the cold gas arises from the fact that
the cavity field can produce density oscillations in the gas which in turn acts
as an internal Bragg mirror for the field. After adiabatic elimination of the
cavity field we find that the hybrid system of the gas and mirror is described
by a beam splitter Hamiltonian that allows for state transfer, but only if the
quantum nature of the cavity field is retained.
