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arXiv · 1804.07741

Scalar Bispectrum Beyond Slow-Roll in the Unified EFT of Inflation

Samuel Passaglia·Wayne Hu
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Abstract

We present a complete formulation of the scalar bispectrum in the unified effective field theory (EFT) of inflation, which includes the Horndeski and beyond-Horndeski Gleyzes-Langlois-Piazza-Vernizzi classes, in terms of a set of simple one-dimensional integrals. These generalized slow-roll expressions remain valid even when slow-roll is transiently violated and encompass all configurations of the bispectrum. We show analytically that our expressions explicitly preserve the squeezed-limit consistency relation beyond slow-roll. As an example application of our results, we compute the scalar bispectrum in a model in which potential-driven G-inflation at early times transitions to chaotic inflation at late times, showing that our expressions accurately track the bispectrum when slow-roll is violated and conventional slow-roll approximations fail.

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Samuel Passaglia, Wayne Hu. 2018-04-20. Scalar Bispectrum Beyond Slow-Roll in the Unified EFT of Inflation. https://doi.org/10.1103/physrevd.98.023526

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