Mimetic gravity as DHOST theories
General Relativity and Quantum Cosmology
2019-03-19 v2 Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
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 -essence scalar field, and we derive the quadratic action for linear perturbations in this case.
Cite
@article{arxiv.1802.03394,
title = {Mimetic gravity as DHOST theories},
author = {David Langlois and Michele Mancarella and Karim Noui and Filippo Vernizzi},
journal= {arXiv preprint arXiv:1802.03394},
year = {2019}
}
Comments
22 pages, 1 figure, references added and discussion on the instability modified. Matches the version published on JCAP