Exploring gravitational theories beyond Horndeski

Journal Article · Sun Feb 01 04:00:00 EST 2015 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2015/02/018· OSTI ID:22381986

Gleyzes, Jérôme; Vernizzi, Filippo ^[1]; Langlois, David; Piazza, Federico ^[2]

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1. CEA, IPhT, 91191 Gif-sur-Yvette cédex, France CNRS, URA-2306, 91191 Gif-sur-Yvette cédex (France)
2. APC, (CNRS-Université Paris 7), 10 rue Alice Domon et Léonie Duquet, 75205 Paris (France)

We have recently proposed a new class of gravitational scalar-tensor theories free from Ostrogradski instabilities, in ref. [1]. As they generalize Horndeski theories, or ''generalized'' galileons, we call them G{sup 3}. These theories possess a simple formulation when the time hypersurfaces are chosen to coincide with the uniform scalar field hypersurfaces. We confirm that they contain only three propagating degrees of freedom by presenting the details of the Hamiltonian formulation. We examine the coupling between these theories and matter. Moreover, we investigate how they transform under a disformal redefinition of the metric. Remarkably, these theories are preserved by disformal transformations that depend on the scalar field gradient, which also allow to map subfamilies of G{sup 3} into Horndeski theories.

• OSTI ID: 22381986
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 02 Vol. 2015; ISSN 1475-7516
• Country of Publication: United States
• Language: English

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