Cosmological evolution in bimetric gravity: observational constraints and LSS signatures

Abstract

Bimetric gravity is an interesting alternative to standard GR given its potential to provide a concrete theoretical framework for a ghost-free massive gravity theory. Here we investigate a class of Bimetric gravity models for their cosmological implications. We study the background expansion as well as the growth of matter perturbations at linear and second order. We use low-redshift observations from SnIa (Pantheon+ and SH0ES), Baryon Acoustic Oscillations (BAO), the growth ($$f\sigma _{8}$$ f σ 8 ) measurements and the measurement from Megamaser Cosmology Project to constrain the Bimetric model. We find that the Bimetric models are consistent with the present data alongside the $$\Lambda $$ Λ CDM model. We reconstructed the “ effective dark energy equation of state”($$\omega _{de}$$ ω de ) and “Skewness”($$S_{3}$$ S 3 ) parameters for the Bimetric model from the observational constraints and show that the current low-redshift data allow significant deviations in $$\omega _{de}$$ ω de and $$S_{3}$$ S 3 parameters with respect to the $$\Lambda $$ Λ CDM behaviour. We also look at the ISW effect via galaxy-temperature correlations and find that the best fit Bimetric model behaves similarly to $$\Lambda $$ Λ CDM in this regard.

Fractional Scalar Field Cosmology

“…which is employed to indicate the constraint Equation (30) in terms of the minisuperspace coordinate:…”

“…Therefore, to address the problems with the observed discrepancies and limitations of the ΛCDM model, various generalized models have been proposed, including modified gravity models, such as MOND (Modified Newtonian Dynamics) [20,21], f (R) gravity [22][23][24][25], entropic gravity [26,27], bimetric gravity [28][29][30][31][32] minimally coupled Einstein scalar field system [33][34][35]; scalar-tensor theories [36][37][38][39], specifically, the Brans-Dicke theory [40][41][42], and their corresponding noncommutative extensions [43][44][45][46]; generalized Chaplygin gas models [47,48]; and establishing modified fundamental models from their corresponding standard ones in higher dimensions [49][50][51][52][53][54].…”