We show that theories of mimetic gravity can be viewed as degenerate higher-order scalar-tensor (DHOST) theories that admit an extra local (gauge) symmetry in addition to the usual diffeomorphism invariance. We reformulate and classify mimetic theories in this perspective. Using the effective theory of dark energy, recently extended to include DHOST theories, we then investigate the linear perturbations about a homogeneous and isotropic background for all mimetic theories. We also include matter, in the form of a k-essence scalar field, and we derive the quadratic action for linear perturbations in this case.

Langlois, D., Mancarella, M., Noui, K., Vernizzi, F. (2019). Mimetic gravity as DHOST theories. JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 2019(2) [10.1088/1475-7516/2019/02/036].

Mimetic gravity as DHOST theories

Mancarella M.;
2019

Abstract

We show that theories of mimetic gravity can be viewed as degenerate higher-order scalar-tensor (DHOST) theories that admit an extra local (gauge) symmetry in addition to the usual diffeomorphism invariance. We reformulate and classify mimetic theories in this perspective. Using the effective theory of dark energy, recently extended to include DHOST theories, we then investigate the linear perturbations about a homogeneous and isotropic background for all mimetic theories. We also include matter, in the form of a k-essence scalar field, and we derive the quadratic action for linear perturbations in this case.
Articolo in rivista - Articolo scientifico
Cosmological perturbation theory; Dark energy theory; Modified gravity;
English
2019
2019
2
036
none
Langlois, D., Mancarella, M., Noui, K., Vernizzi, F. (2019). Mimetic gravity as DHOST theories. JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 2019(2) [10.1088/1475-7516/2019/02/036].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/400837
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