2014/03/27 by L. Fatibene, S. Garruto · 1 citation
Physics and Astronomy · #gr-qc
paper · pdf · doi:10.1142/s0219887814600184
arxiv created 2014/03/27 · arxiv updated 2014/09/29
We shall show equivalence between Palatini-f(\calR) theories and Brans-Dicke (BD) theories at the level of action principles in generic dimension with generic matter coupling. We do that by introducing the Helmholtz Lagrangian associated to Palatini-f(\calR) theory and then performing frame transformations in order to recover Einstein frame and Brans-Dicke frame. This clarifies the relation among different formulations and the transformations among different frames. Additionally, it defines a formulation \it a lá Palatini for the Brans-Dicke theory which is dynamically equivalent to metric BD (unlike the standard Palatini-formulation of metric BD theory which are \it not dynamically equivalent). In conclusion we discuss interpretation of extended theories of gravitation and perspectives.