Strong coupling in brane-induced gravity in five dimensions
arXiv:hep-th/0303125
Abstract
Brane-induced gravity in five dimensions (Dvali--Gabadadze--Porrati model) exhibits modification of gravity at ultra-large distances, where is the five-dimensional gravity scale. This makes the model potentially interesting for explaining the observed acceleration of the Universe. We argue, however, that it has an intrinsic intermediate energy scale . At higher energies, the model is strongly coupled. For of order of the present Hubble size, the strong coupling regime occurs at distanced below tens of metres.