The Effective Field Theory of Inflation

By Clifford Cheung, A. Fitzpatrick, Jared Kaplan, L. Senatore, P. Creminelli. 2007

678 citations recorded by the source corpus.

We study the effective field theory of inflation, i.e. the most general theory describing the fluctuations around a quasi de Sitter background, in the case of single field models. The scalar mode can be eaten by the metric by going to unitary gauge. In this gauge, the most general theory is built with the lowest dimension operators invariant under spatial diffeomorphisms, like g00 and Kμν, the extrinsic curvature of constant time surfaces. This approach allows us to characterize all the possible high energy corrections to simple slow-roll inflation, whose sizes are constrained by experiments. Also, it describes in a common language all single field models, including those with a small speed of sound and Ghost Inflation, and it makes explicit the implications of having a quasi de Sitter background. The non-linear realization of time diffeomorphisms forces correlation among different observables, like a reduced speed of sound and an enhanced level of non-Gaussianity.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a8ebf1a22d5916a2f89472b5089e8b9c0adcd839

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Citations in the corpus

The cosmological bootstrap: inflationary correlators from symmetries and singularities (2018, neutral): “conformal symmetry more strongly, as in models with a reduced sound speed of the inflationary fluctuations [59, 115–117], or strongly coupled fluctuations, as in some holographic models of dS/CFT [118].”
Challenges and opportunities of gravitational-wave searches at MHz to GHz frequencies (2020, background): “In the standard single-field effective field theory of inflation (Cheung et al. 2008) only time-translation symmetry (t ! t þ n0) is broken according to the cosmological background expansion during inflation.”
The effective field theory of cosmological large scale structures (2012, background): “An important early (and recent) application of these techniques in cosmology is the so-called Effective Field Theory of Inflation [1, 2].”
Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, positive): “…characterized by more general higher-derivative interactions, such as ghost inflation (Arkani-Hamed et al. 2004), effective field theories of inflation (Cheung et al. 2008; Senatore et al. 2010; Bartolo et al. 2010a), or the so “Galileon-like” models of inflation (see, e.g., Burrage et al. 2011).”
Effective theories of single field inflation when heavy fields matter (2012, background): “Qualifying the expectation that cs can at most be a slowly varying function of time [1], or that it cannot become too small without violating perturbative unitarity [25], we find that it is entirely consistent to have transiently small speeds of sound induced by transient strong couplings of various”
Inflation and String Theory (2014, methodology): “At cubic order and to lowest order in derivatives, we get [51] (see Appendix B for the derivation)”
Effective field theory approach to quasi-single field inflation and effects of heavy fields (2012, methodology): “5 Extending the procedures in [38] to our case, the most general action invariant under the time-dependent spatial diffeomorphism is given by”
Science with the space-based interferometer LISA. IV: probing inflation with gravitational waves (2016, methodology): “With the same spirit of the EFT of inflation [117], our constraints on the physical observables of the theory, automatically translate to operators appearing in the quadratic action for the tensor field.”