# The effective field theory of K-mouflage

Abstract : We describe K-mouflage models of modified gravity using the effective field theory of dark energy. We show how the Lagrangian density $K$ defining the K-mouflage models appears in the effective field theory framework, at both the exact fully nonlinear level and at the quadratic order of the effective action. We find that K-mouflage scenarios only generate the operator $(\delta g^{00}_{(u)})^n$ at each order $n$. We also reverse engineer K-mouflage models by reconstructing the whole effective field theory, and the full cosmological behaviour, from two functions of the Jordan-frame scale factor in a tomographic manner. This parameterisation is directly related to the implementation of the K-mouflage screening mechanism: screening occurs when $K'$ is large in a dense environment such as the deep matter and radiation eras. In this way, K-mouflage can be easily implemented as a calculable subclass of models described by the effective field theory of dark energy which could be probed by future surveys.
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Journal articles
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https://hal-cea.archives-ouvertes.fr/cea-01201562
Contributor : Emmanuelle de Laborderie <>
Submitted on : Wednesday, February 24, 2021 - 2:11:39 PM
Last modification on : Wednesday, April 14, 2021 - 12:12:22 PM
Long-term archiving on: : Tuesday, May 25, 2021 - 6:38:47 PM

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### Citation

Philippe Brax, Patrick Valageas. The effective field theory of K-mouflage. Journal of Cosmology and Astroparticle Physics, Institute of Physics (IOP), inPress, 2016 (01), pp.020. ⟨10.1088/1475-7516/2016/01/020⟩. ⟨cea-01201562⟩

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