Power Spectra beyond the Slow Roll Approximation in Theories with   Non-Canonical Kinetic Terms
  We derive analytical expressions for the power spectra at the end of inflation in theories with two inflaton fields and non-canonical kinetic terms. We find that going beyond the slow-roll approximation is necessary and that the nature of the non-canonical terms have an important impact on the final power spectra at the end of inflation. We study five models numerically and find excellent agreement with our analytical results. Our results emphasise the fact that going beyond the slow-roll approximation is important in times of high-precision data coming from cosmological observations. 
Carsten van de Bruck and Mathew Robinson
astro-ph.CO hep-th