Trapped Brane Features in DBI Inflation
  We consider DBI inflation with a quadratic potential and the effect of
trapped branes on the inflationary fluctuations. When going through a trapped
brane the effective potential of the inflaton receives a contribution whose
effect is to induce a jump in the power spectrum of the inflaton perturbations.
This feature appears in the power spectrum at a scale corresponding to the size
of the sound horizon when the two branes cross each other.
