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arXiv · 1708.04262

Perturbations in generalized Galileon theories

R. Kolevatov·S. Mironov·V. Rubakov·N. Sukhov·V. Volkova
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Abstract

We discuss the approaches by Deffayet et al. (DPSV) and Kobayashi et al. (KYY) to the analysis of linearized scalar perturbations about a spatially flat FLRW background in Horndeski theory. We identify additional, potentially important terms in the DPSV approach. However, these terms vanish upon a judicious gauge choice. We derive a gauge invariant quadratic action for metric and Galileon perturbations in $\mathcal{L}_3$ and $\mathcal{L}_3+\mathcal{L}_4$ theories and show that actions obtained in the DPSV and KYY approaches follow from this gauge invariant action in particular gauges.

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R. Kolevatov, S. Mironov, V. Rubakov, N. Sukhov, V. Volkova. 2017-08-14. Perturbations in generalized Galileon theories. https://doi.org/10.1103/physrevd.96.125012

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