Constraints on bimetric gravity from Big Bang nucleosynthesis
Abstract
Bimetric gravity is a ghostfree and observationally viable extension of general relativity, exhibiting both a massless and a massive graviton. The observed abundances of light elements can be used to constrain the expansion history of the Universe at the period of Big Bang nucleosynthesis. Applied to bimetric gravity, we readily obtain constraints on the theory parameters which are complementary to other observational probes. For example, the mixing angle between the two gravitons must satisfy $\theta \lesssim 18^\circ$ in the graviton mass range $m_\mathrm{FP} \gtrsim 10^{16} \, \mathrm{eV}/c^2$, representing a factor of two improvement compared with other cosmological probes.
 Publication:

arXiv eprints
 Pub Date:
 June 2021
 arXiv:
 arXiv:2106.09030
 Bibcode:
 2021arXiv210609030H
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 4 pages, comments are welcome. For a short (5 min) video summarizing the main result, see https://youtu.be/uqdbOZQ7k_k