Oscillatory features in the curvature power spectrum after a sudden turn of the inflationary trajectory

Xian Gao, David Langlois, Shuntaro Mizuno

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29 Citations (Scopus)


In the context of two-field inflation characterized by a light direction and a heavy direction, we revisit the question of the impact of the massive modes on the power spectrum produced after a turn in the inflationary trajectory. We consider in particular the resonant effect due to the background oscillations following a sharp turn. Working in the mass basis, i.e. in the basis spanned by the eigenvectors of the effective mass matrix for the perturbations, we provide an analytical estimate of the resonant effect, using the in-in formalism. In comparison with earlier estimates, we find the same the spectral dependence but a smaller amplitude. We also compute, again via the in-in formalism, the effect of the direct coupling between the light and heavy modes at the instant of the turn and confirm our previous results obtained via a different method.

Original languageEnglish
Article number023
JournalJournal of Cosmology and Astroparticle Physics
Issue number10
Publication statusPublished - 2013 Oct
Externally publishedYes



  • cosmological perturbation theory
  • inflation

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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