Heavy fields, reduced speeds of sound and decoupling during inflation

By Ana Achúcarro, Vicente Atal, Sebastián Céspedes, Jinn-Ouk Gong, G. Palma, S. Patil. 2012

146 citations recorded by the source corpus.

We discuss and clarify the validity of effective single field theories of inflation obtained by integrating out heavy degrees of freedom in the regime where adiabatic perturbations propagate with a suppressed speed of sound. We show by construction that it is indeed possible to have inflationary backgrounds where the speed of sound remains suppressed and slow-roll persists for long enough. In this class of models, heavy fields influence the evolution of adiabatic modes in a manner that is consistent with decoupling of physical low and high energy degrees of freedom. We emphasize the distinction between the effective masses of the isocurvature modes and the eigenfrequencies of the propagating high energy modes. Crucially, we find that the mass gap that defines the high frequency modes increases with the strength of the turn, even as the naive heavy (isocurvature) and light (curvature) modes become more strongly coupled. Adiabaticity is preserved throughout, and the derived effective field theory remains in the weakly coupled regime, satisfying all current observational constraints on the resulting primordial power spectrum. In addition, these models allow for an observably large equilateral non-Gaussianity.

Subfields: Astronomy and Astrophysics, Oceanography

View Paper: https://www.semanticscholar.org/paper/630e1b5b7e63669f205c75561c97442193b22ca9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

  1. D. Baumann
  2. Liam McAllister
  3. E. Pajer
  4. Thomas W. Grimm
  5. Eran Palti
  6. Andrei Linde
  7. L. Senatore
  8. E. Silverstein

In Oceanography

  1. D. Baumann
  2. Liam McAllister

Citations in the corpus