Combined features in the primordial spectra induced by a sudden turn in two-field DBI inflation

Shuntaro Mizuno*, Ryo Saito, David Langlois

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


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.

Original languageEnglish
Article number032
JournalJournal of Cosmology and Astroparticle Physics
Issue number11
Publication statusPublished - 2014 Nov 1
Externally publishedYes


  • Cosmological perturbation theory
  • Inflation

ASJC Scopus subject areas

  • Astronomy and Astrophysics


Dive into the research topics of 'Combined features in the primordial spectra induced by a sudden turn in two-field DBI inflation'. Together they form a unique fingerprint.

Cite this