Conformal transformations and weak field limit of scalar-tensor gravity

The weak-field limit of scalar-tensor theories of gravity is discussed in view of conformal transformations. Specifically, we consider how physical quantities - such as gravitational potentials derived in the Newtonian approximation for the same scalar-tensor theory - behave in the Jordan and Einstein frames. The approach allows one to discriminate features that are invariant under conformal transformations and gives contributions to the debate of how to select the true physical frame. As a particular example, the case of f(R) gravity is considered. © 2013 American Physical Society.