Probing cosmological fields with gravitational wave oscillations
Abstract
Gravitational wave (GW) oscillations occur whenever there are additional tensor modes interacting with the perturbations of the metric coupled to matter. These extra modes can arise from new spin2 fields (as in e.g. bigravity theories) or from nontrivial realizations of the cosmological principle induced by background vector fields with internal symmetries (e.g. YangMills, gaugids or multiProca). We develop a general cosmological framework to study such novel features due to oscillations. The evolution of the two tensor modes is described by a linear system of coupled second order differential equations exhibiting friction, velocity, chirality and mass mixing. We follow appropriate schemes to obtain approximate solutions for the evolution of both modes and show the corresponding phenomenology for different mixings. Observational signatures include modulations of the waveform, oscillations of the GW luminosity distance, anomalous GW speed and chirality. We discuss the prospects of observing these effects with present and future GW observatories such as LIGO/VIRGO and LISA.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 April 2020
 DOI:
 10.1088/14757516/2020/04/027
 arXiv:
 arXiv:1912.06104
 Bibcode:
 2020JCAP...04..027B
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 36 pages, 9 figures. Matches JCAP version