Combined features in the primordial spectra induced by a sudden turn in
  two-field DBI inflation
  We investigate the features generated by a sharp turn along the inflationary
trajectory in a two-field model of Dirac-Born-Infeld inflation, where one of
the fields is heavy. Distinct features are generated by two different effects:
the mixing of the light and heavy modes during the turn, on the one hand, and
the resonance between the oscillations along the heavy direction after the
turn, on the other hand. Contrary to models with standard kinetic terms, the
resonance effect is not strongly suppressed because the action contains
derivative interactions. Working in the potential basis, we study the
oscillations after the turn and compute the amplitude of the mixing and
resonance features in the power spectrum, as well as in the bispectrum for the
latter effect. We find that the amplitudes and positions of these combined
features obey specific consistency relations, which could be confronted with
cosmological data.
