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Title: Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings

Abstract

We study generalized disformal transformations, including derivatives of the metric, in the context of the Effective Field Theory of Inflation. All these transformations do not change the late-time cosmological observables but change the coefficients of the operators in the action: some couplings are effectively redundant. At leading order in derivatives and up to cubic order in perturbations, one has 6 free functions that can be used to set to zero 6 of the 17 operators at this order. This is used to show that the tensor three-point function cannot be modified at leading order in derivatives, while the scalar-tensor-tensor correlator can only be modified by changing the scalar dynamics. At higher order in derivatives there are transformations that do not affect the Einstein-Hilbert action: one can find 6 additional transformations that can be used to simplify the inflaton action, at least when the dynamics is dominated by the lowest derivative terms. We also identify the leading higher-derivative corrections to the tensor power spectrum and bispectrum.

Authors:
 [1];  [2];  [3];  [4]
  1. SISSA, via Bonomea 265, 34136, Trieste (Italy)
  2. Physics Department and INFN, Università di Roma 'La Sapienza', P.le Aldo Moro 2, 00185, Rome (Italy)
  3. Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy)
  4. Institut de physique théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette (France)
Publication Date:
OSTI Identifier:
22667668
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2017; Journal Issue: 09; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CORRECTIONS; DISTURBANCES; FIELD THEORIES; HILBERT TRANSFORMATION; INFLATIONARY UNIVERSE; INFLATONS; METRICS; PERTURBATION THEORY; SPECTRA; TRANSFORMATIONS

Citation Formats

Bordin, Lorenzo, Cabass, Giovanni, Creminelli, Paolo, and Vernizzi, Filippo, E-mail: lbordin@sissa.it, E-mail: giovanni.cabass@roma1.infn.it, E-mail: creminel@ictp.it, E-mail: filippo.vernizzi@cea.fr. Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings. United States: N. p., 2017. Web. doi:10.1088/1475-7516/2017/09/043.
Bordin, Lorenzo, Cabass, Giovanni, Creminelli, Paolo, & Vernizzi, Filippo, E-mail: lbordin@sissa.it, E-mail: giovanni.cabass@roma1.infn.it, E-mail: creminel@ictp.it, E-mail: filippo.vernizzi@cea.fr. Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings. United States. doi:10.1088/1475-7516/2017/09/043.
Bordin, Lorenzo, Cabass, Giovanni, Creminelli, Paolo, and Vernizzi, Filippo, E-mail: lbordin@sissa.it, E-mail: giovanni.cabass@roma1.infn.it, E-mail: creminel@ictp.it, E-mail: filippo.vernizzi@cea.fr. Fri . "Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings". United States. doi:10.1088/1475-7516/2017/09/043.
@article{osti_22667668,
title = {Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings},
author = {Bordin, Lorenzo and Cabass, Giovanni and Creminelli, Paolo and Vernizzi, Filippo, E-mail: lbordin@sissa.it, E-mail: giovanni.cabass@roma1.infn.it, E-mail: creminel@ictp.it, E-mail: filippo.vernizzi@cea.fr},
abstractNote = {We study generalized disformal transformations, including derivatives of the metric, in the context of the Effective Field Theory of Inflation. All these transformations do not change the late-time cosmological observables but change the coefficients of the operators in the action: some couplings are effectively redundant. At leading order in derivatives and up to cubic order in perturbations, one has 6 free functions that can be used to set to zero 6 of the 17 operators at this order. This is used to show that the tensor three-point function cannot be modified at leading order in derivatives, while the scalar-tensor-tensor correlator can only be modified by changing the scalar dynamics. At higher order in derivatives there are transformations that do not affect the Einstein-Hilbert action: one can find 6 additional transformations that can be used to simplify the inflaton action, at least when the dynamics is dominated by the lowest derivative terms. We also identify the leading higher-derivative corrections to the tensor power spectrum and bispectrum.},
doi = {10.1088/1475-7516/2017/09/043},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 09,
volume = 2017,
place = {United States},
year = {2017},
month = {9}
}