1302.4300 (Metin Arik et al.)

Modified Gravity with Matter Curvature Coupling Induced by the Norm of
the Stress-energy Tensor    [PDF]

Metin Arik, Mehmet Kavuk

In this work, we consider modified theories of gravity, where Einstein-Hilbert lagrangian in General Relativity(GR) is replaced by an arbitrary function of the Ricci scalar R and of the norm of the stress-energy tensor. By varying the action with respect to the metric we obtain the gravitational field equations. For a specific choice of the function where Ricci scalar is minimally coupled to the norm of the stress-energy tensor we reconstruct some FRW cosmologies. Upon examining the geodesic equations of massive particles it is seen that they do not move on geodesics but are rather acted upon by a force which is orthogonal to the four-velocity of the particles.

View original: http://arxiv.org/abs/1302.4300