Inhomogeneous Reheating Scenario with DBI fields
  We discuss a new mechanism which can be responsible for the origin of the
primordial perturbation in inflationary models, the inhomogeneous DBI reheating
scenario. Light DBI fields fluctuate during inflation, and finally create the
density perturbations through modulation of the inflation decay rate. In this
note, we investigate the curvature perturbation and its non-Gaussianity from
this new mechanism. Presenting generalized expressions for them, we show that
the curvature perturbation not only depends on the particular process of decay
but is also dependent on the sound speed $c_s$ from the DBI action. More
interestingly we find that the non-Gaussianity parameter $f_{NL}$ is
independent of $c_s$. As an application we exemplify some decay processes which
give a viable and detectable non-Gaussianity. Finally we find a possible
connection between our model and the DBI-Curvaton mechanism.
