Ekpyrotic Reheating and Fate of Inflaton
  It is shown that perturbative reheating can reach a sufficiently high
temperature with small or negligible inflaton decay rate provided that the
inflaton potential becomes negative after inflation. In our model, inflaton and
dark energy field are two independent scalar fields, and, depending on the mass
of the inflaton and its coupling to matter fields, there is a possibility that
the remaining inflaton after reheating can become a dark matter candidate.
