Gradient expansion of superhorizon perturbations in G-inflation

Abstract

We develop the gradient expansion formalism for shift-symmetric Galileon-type actions. We focus on backgrounds that undergo inflation, work in the synchronous gauge, and obtain a general solution up to second order without imposing extra conditions at first order. The solution simplifies during the late stages of inflation. We also define a curvature perturbation conserved up to first order.

20 pages, JCAP version

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Cited by in corpus (6)

• Black hole hair in generalized scalar-tensor gravity: An explicit example
• An Extended action for the effective field theory of dark energy: a stability analysis and a complete guide to the mapping at the basis of EFTCAMB
• Multi-field G-inflation
• On the Trispectrum of Galileon Inflation
• Tackling non-linearities with the effective field theory of dark energy and modified gravity
• Constraining cosmological scaling solutions of a Galileon field