The sound of DHOST
General Relativity and Quantum Cosmology
2019-04-02 v2 Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
Abstract
We show that, in generic higher-order scalar-tensor theories which avoid the Ostrogradsky instability, the presence of a scalar field significantly modifies the propagation of matter perturbations, even in weakly curved backgrounds. This affects notably the speed of sound in the atmosphere of the Earth. It can also generate instabilities in homogeneous media. We use this to constrain the viable higher-order scalar-tensor models.
Cite
@article{arxiv.1810.09997,
title = {The sound of DHOST},
author = {Eugeny Babichev and Antoine Lehébel},
journal= {arXiv preprint arXiv:1810.09997},
year = {2019}
}
Comments
10 pages, 2 figures. Appendix added in second version