Notes on the Chameleon Brans-Dicke Gravity
arXiv:1402.4779 · doi:10.1007/s10509-013-1751-4
Abstract
We consider a generalized Brans-Dicke model in which the scalar field has a potential function and is also allowed to couple non-minimally with the matter sector. This anomalous gravitational coupling can in principle avoid the model to pass local gravity experiments. One then usually assumes that the scalar field has a chameleon behavior in the sense that it acquires a density-dependent effective mass. While it can take a small effective mass in cosmological (low-density environment) scale, it has a sufficiently heavy mass in Solar System (large-density environment) and then hides gravity tests. We will argue that such a chameleon behavior can not be generally realized and depends significantly on the forms attributed to the potential and the coupling functions.
9 pages, no figure. To appear in Astrophysics and Space Science. arXiv admin note: text overlap with arXiv:0907.3838, arXiv:1005.5670, arXiv:1212.2709