http://arxiv.org/abs/1512.05232
In this letter, we show that there exists a class of dilaton models with non-trivial scalar-Ricci and scalar-matter couplings that strongly reduces deviations from general relativity in the dust limit. These models turn out to be special cases of the more general dilaton that will be studied in more detail in an upcoming publication. Depending essentially on the coupling between the dilaton and the fundamental matter fields, various strength of decouplings are uncovered. They range from almost no decoupling to a total decoupling state. In this latter case, the theory becomes indistinguishable from general relativity as all dilatonic effects can be re-absorbed through a simple change of units — even though there is a non-minimal and non-trivial coupling between the dilaton and matter. But each strength of decoupling has the effect of reducing possible departures from the phenomenology of general relativity. The class of non-dynamical decouplings proposed in this letter might play a role in the current non-observation of any deviation from general relativity (in both the equivalence principle and the parametrized post-Newtonian sectors).
O. Minazzoli and A. Hees
Thu, 17 Dec 15
20/55
Comments: letter, 6 pages, comments welcome