  We study the limitations to the relative number squeezing between photons and
atoms coupled out from a homogeneous Bose-Einstein-Condensate. We consider the
coupling between the translational atomic states by two photon Bragg processes,
with one of the photon modes involved in the Bragg process in a coherent state,
and the other initially unpopulated. We start with an interacting Bose-
condensate at zero temperature and compute the time evolution for the system.
We study the squeezing, i.e. the variance of the occupation number difference
between the second photon and the atomic c.m. mode. We discuss how collisions
between the atoms and photon rescattering affect the degree of squeezing which
may be reached in such experiments.
