Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings
- SISSA, via Bonomea 265, 34136, Trieste (Italy)
- Physics Department and INFN, Università di Roma 'La Sapienza', P.le Aldo Moro 2, 00185, Rome (Italy)
- Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy)
- Institut de physique théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette (France)
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.
- OSTI ID:
- 22667668
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2017, Issue 09; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
Disformal invariance of cosmological perturbations in a generalized class of Horndeski theories
Disformal invariance of cosmological perturbations in a generalized class of Horndeski theories