Post-post-newtonian Limit of a Dilatonic Gravity Model

Abstract

We study a solution of the field equations for dilatonic gravity and obtain its post-post-newtonian limit. It turns out that terms to this and higher orders in the expansion may become important in strong gravitational fields, even though the post-newtonian limit coincides with that of General Relativity. This suggests that strong gravitational fields can only be studied by exact solutions of the field equations. In recent years there has been an increasing interest in tensor-scalar theories of gravity, as they arise naturally in several unification models. However, for the slow motion, weak field limit, the PPN formalism [1] has proved to be a very powerful tool to restrict theories that are phisically viable. On the other hand, with binary pulsar observations the tests of the strong field regime have begun, but again, the measurements have further limited the possible alternatives to General Relativity [2]. Here we will suggest, by means of an example, that the PPN framework may be incomplete, and therefore, that exact solutions to the field equations may be the only way to describe certain aspects of physical systems in strong fields. email:tmatos@fis.cinvestav.mx email:brena@fis.cinvestav.mx

Cite this paper

@inproceedings{Matos2008PostpostnewtonianLO, title={Post-post-newtonian Limit of a Dilatonic Gravity Model}, author={Tonatiuh Matos and Hugo Villegas-Brena}, year={2008} }