A general mass term for bigravity
Cosmology and Nongalactic Astrophysics
2016-05-04 v3 General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
Abstract
We introduce a new formalism to study perturbations of Hassan-Rosen bigravity theory, around general backgrounds for the two dynamical metrics. In particular, we derive the general expression for the mass term of the perturbations and we explicitly compute it for cosmological settings. We study tensor perturbations in a specific branch of bigravity using this formalism. We show that the tensor sector is affected by a late-time instability, which sets in when the mass matrix is no longer positive definite.
Cite
@article{arxiv.1512.02131,
title = {A general mass term for bigravity},
author = {Giulia Cusin and Ruth Durrer and Pietro Guarato and Mariele Motta},
journal= {arXiv preprint arXiv:1512.02131},
year = {2016}
}
Comments
27 pages, 24 figures; v3: version accepted for publication in JCAP