On the Instability of the Lee-Wick Bounce
  It was recently realized that a model constructed from a Lee-Wick type scalar
field theory yields, at the level of homogeneous and isotropic background
cosmology, a bouncing cosmology. However, bouncing cosmologies induced by
pressure-less matter are in general unstable to the addition of relativistic
matter (i.e. radiation). Here we study the possibility of obtaining a bouncing
cosmology if we add radiation coupled to the Lee-Wick scalar field. This
coupling in principle would allow the energy to flow from radiation to matter,
thus providing a drain for the radiation energy. However, we find that it takes
an extremely unlikely fine tuning of the initial phases of the field
configurations for a sufficient amount of radiative energy to flow into matter.
For general initial conditions, the evolution leads to a singularity rather
than a smooth bounce.
