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Title: Exploring gravitational theories beyond Horndeski

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.
Authors:
;  [1] ; ;  [2]
  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)
Publication Date:
OSTI Identifier:
22381986
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 02; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COUPLING; DEGREES OF FREEDOM; HAMILTONIANS; INSTABILITY; MATTER; METRICS; SCALAR FIELDS; SCALARS; TENSORS; TRANSFORMATIONS