Matter creation in a nonsingular bouncing cosmology
  We examine reheating in the two-field matter bounce cosmology. In this model,
the universe evolves from a matter-dominated phase of contraction to an
Ekpyrotic phase of contraction before the nonsingular bounce. The Ekpyrotic
phase frees the model from unwanted anisotropies, but leaves the universe cold
and empty of particles after the bounce. For this reason, we explore two
particle production mechanisms which take place during the course of the
cosmological evolution: Parker particle production where the matter field
couples only to gravity and particle creation via interactions between the
matter field and the bounce field. Although we show that both mechanisms can
produce particles in this model, we find that Parker particle production is
sufficient to reheat the universe to high temperatures. Thus there is {\it{a
priori}} no need to add an interaction term to the Lagrangian of the model.
Still, particle creation via interactions can contribute to the formation of
matter and radiation, but only if the coupling between the fields is tuned to
be large.
