2021/01/31 by Marcus Högås, Edvard Mörtsell
Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Classical mechanics #Cosmic microwave background #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #General relativity #Gravitation #Graviton #Massive gravity #Massless particle #Mathematical physics #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Theoretical physics #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2021/05/002
20 pages, 15 figures + appendices. A short video summarizing the results can be found here: "https://youtu.be/u9nHGoP0iOU". Version 2, very slight modification according to the published version
openalex publication_date 2021/05/01 · arxiv created 2021/05/10 · openalex created_date 2021/05/10 · arxiv updated 2021/05/19 · openalex updated_date 2026/07/30
Abstract Ghost-free bimetric gravity is a theory of two interacting spin-2 fields, one massless and one massive, in addition to the standard matter particles and fields, thereby generalizing Einstein's theory of general relativity. To parameterize the theory, we use five observables with specific physical interpretations. We present, for the first time, observational constraints on these parameters that: (i) apply to the full theory, (ii) are consistent with a working screening mechanism (i.e., restoring general relativity locally), (iii) exhibit a continuous, real-valued background cosmology (without the Higuchi ghost). For the cosmological constraints, we use data sets from the cosmic microwave background, baryon acoustic oscillations, and type Ia supernovae. Bimetric cosmology provides a good fit to data even for large values of the mixing angle between the massless and massive gravitons. Interestingly, the best-fit model is a self-accelerating solution where the accelerated expansion is due to the dynamical massive spin-2 field, without a cosmological constant. Due to the screening mechanism, the models are consistent with local tests of gravity such as solar system tests and gravitational lensing by galaxies. We also comment on the possibility of alleviating the Hubble tension with this theory.