Solar System Tests in Brans-Dicke and Palatini f(R)-theories

Abstract

We compare Mercury's precession test in standard General Relativity (GR), Brans-Dicke theories (BD), and Palatini f (R)-theories. We avoid post Newtonian (PN) approximation and compute exact precession in these theories. We show that the well-known mathematical equivalence between Palatini f (R)-theories and a specific subset of BD theories does not extend to a really physical equivalence among theories since equivalent models still allow different incompatible precession for Mercury depending on the solution one chooses. As a result one cannot use BD equivalence to rule out Palatini f (R)-theories. On the contrary, we directly discuss that Palatini f (R)-theories can (and specific models do) easily pass Solar System tests as Mercury's precession.

Cooling process of brown dwarfs in Palatini f(R) gravity

“…Furthermore, Palatini gravity alters the early Universe physics, explains the acceler-ation expansion of the late Universe, provides different black hole solutions or produces wormholes with no exotic fluid . It passes current solar system tests [45] since the modifications of energy and momentum appearing in Euler equation turn out not to be sensitive enough to the experiments performed for the solar system orbits [46]. The situation may however change when experiments on an atomic level will be available [47][48][49].…”