http://arxiv.org/abs/2303.11353
Bimetric gravity, is a theory of gravity that posits the existence of two interacting and dynamical metric tensors. The spectrum of bimetric gravity consists of a massless and a massive spin-2 particle. The form of the interactions between the two metrics $g_{\mu\nu}$ and $f_{\mu\nu}$ is constrained by requiring absence of the so called Boulware-Deser ghost. In this work we extend the original bimetric theory to its bimetric-affine counterpart, in which the associated two connections, $\Gamma_{ \mu\,\,\,\nu}^{\,\,\,\rho}(g)$ and $\widetilde{\Gamma}_{ \mu\,\,\,\nu}^{\,\,\,\rho}(f)$, are treated as independent variables. We examine in detail the case of an additional quadratic in the Ricci scalar curvature term $\mathcal{R}^2(g)$ and we find that this theory is free of ghosts for a wide range of the interaction parameters, not excluding the possibility of a Dark Matter interpretation of the massive spin-2 particle.
I. Gialamas and K. Tamvakis
Wed, 22 Mar 23
41/68
Comments: 10 pages, 2 figures