Long range effects in gravity theories with Vainshtein screening

Abstract

In this paper we study long range modifications of gravity in the consistent framework of bigravity, which introduces a second massive spin-2 field and allows to continuously interpolate between the regime of General Relativity (mediated by a massless spin-2 field) and massive gravity (mediated by a massive spin-2 field). In particular we derive for the first time the equations for light deflection in this framework and study the effect on the lensing potential of galaxy clusters. By comparison of kinematic and lensing mass reconstructions, stringent bounds can be set on the parameter space of the new spin-2 fields. Furthermore, we investigate galactic rotation curves and the effect on the observable dark matter abundance within this

Constraints on bimetric gravity from Big Bang nucleosynthesis

“…The presence of the massless graviton allows gravitational wave observations to be satisfied without severely restricting the parameter * marcus.hogas@fysik.su.se space of the theory [7], as opposed to many other modified gravity models. Bimetric gravity is also compatible with cosmological observations like the cosmic microwave background (CMB), type Ia supernovae (SNIa), and baryon acoustic oscillations (BAO) [8][9][10][11][12][13][14][15] and it exhibits a screening mechanism that restores general relativity results on solar-system scales [16][17][18][19][20][21]. Among the interesting properties of the theory are:…”

“…Part of the need of dark matter in local environments can also be reduced with a scale-dependent gravitational coupling "constant" [19,20,27].…”

Bimetric cosmology is compatible with local tests of gravity

“…9 in Ref. [29]. 6 We conclude that tests of the gravitational law outside the Solar System do not provide constraints on the bimetric parameter space in the region where α 0.1.…”

Dark matter meets quantum gravity

“…In summary, the asymptotic safety scenario for quantum gravity leads to the boundary conditions at the Planck scale displayed in (4), (22) and (10). There is no boundary condition for non-abelian gauge couplings, assuming that they are asymptotically free by themselves.…”

“…The question we address in this paper is, which minimal models with a DM candidate have an ultraviolet (UV) safe embedding into a theory of quantum gravity and what that implies for their available parameter space. While the observations of galaxies and clusters can have substantial uncertainties, when it comes to predicting the exact value of the missing DM component [10], the observations of the cosmic microwave background lead to a very solid measurement of its abundance, which we use as our benchmark Ω DM h 2 ≈ 0.12 [11]. Previous work has found DM mass bounds from the general consideration of unitarity [12,13], our bounds lead to more stringent mass constraints.…”