Lighting the Dark: The Evolution of the Post-Inflationary Universe
  In simple inflationary cosmological scenarios the near-exponential growth can
be followed by a long period in which the Universe is dominated by the
oscillating inflaton condensate. The condensate is initially almost
homogeneous, but perturbations grow gravitationally, eventually fragmenting the
condensate if it is not disrupted more quickly by resonance or prompt
reheating. We show that the gravitational fragmentation of the condensate is
well-described by the Schr\"odinger-Poisson equations and use numerical
solutions to show that large overdensities form quickly after the onset of
nonlinearity. This is the first exploration of this phase of nonlinear dynamics
in the very early universe, which can affect the detailed form of the
inflationary power spectrum and the dark matter fraction when the dark sector
is directly coupled to the inflaton.
