Cosmology of a brane radiating gravitons into the extra dimension.
We study in a self-consistent way the impact of the emission of bulk gravitons on the (homogeneous) cosmology of a three-brane embedded in a five-dimensional spacetime. In the low energy regime, we recover the well known result that the bulk affects the Friedmann equation only via a radiationlike term C/a(4), called dark or Weyl radiation. In the high energy regime, we find that the Weyl parameter C is no longer constant but grows rapidly. Consequently, C today is determined by the past history of the brane universe and depends on the number of relativistic degrees of freedom at the high/low energy transition.
Langlois
David
D
GReCO, Institut d'Astrophysique de Paris, Centre National de la Recherche Scientifique, 98bis Boulevard Arago, 75014 Paris, France.
Sorbo
Lorenzo
L
Rodríguez-Martínez
María
M