Mild bounds on bigravity from primordial gravitational waves

If the amplitude of primordial gravitational waves is measured in the near-future, what could it tell us about bigravity? To address this question, we study massive bigravity theories by focusing on a region in parameter space which is safe from known instabilities. Similarly to investigations on la...

Full description

Saved in:
Bibliographic Details
Published inJournal of cosmology and astroparticle physics Vol. 2015; no. 7
Main Authors Fasiello, Matteo, Ribeiro, Raquel H.
Format Journal Article
LanguageEnglish
Published United States 01.07.2015
Subjects
AMPLITUDES
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COSMOLOGY
GALACTIC EVOLUTION
GRAVITATIONAL WAVES
IMPLEMENTATION
LIMITING VALUES
MASS
POTENTIALS
RECOMBINATION
SPACE
TENSORS
Online AccessGet full text

Cover

More Information
Summary:If the amplitude of primordial gravitational waves is measured in the near-future, what could it tell us about bigravity? To address this question, we study massive bigravity theories by focusing on a region in parameter space which is safe from known instabilities. Similarly to investigations on late time constraints, we implicitly assume there is a successful implementation of the Vainshtein mechanism which guarantees that standard cosmological evolution is largely unaffected. We find that viable bigravity models are subject to far less stringent constraints than massive gravity, where there is only one set of (massive) tensor modes. In principle sensitive to the effective graviton mass at the time of recombination, we find that in our setup the primordial tensor spectrum is more responsive to the dynamics of the massless tensor sector rather than its massive counterpart. We further show there are intriguing windows in the parameter space of the theory which could potentially induce distinct signatures in the B-modes spectrum.
ISSN:1475-7516
1475-7516
DOI:10.1088/1475-7516/2015/07/027