Abstract
The stability criteria for the generalized Brans-Dicke cosmology in a spatially flat, homogeneous and isotropic cosmological model is discussed in the presence of a perfect fluid. The generalization comes through the channel that the Brans-Dicke coupling parameter is allowed to be a function of the scalar field . This generalization can lead to a host of scalar-tensor theories of gravity for various choices of . A very interesting general result has been found. Excepting for the case of a radiation distribution as the choice of the fluid, all other solutions find a natural habitat in the corresponding solutions in general relativity in an infinite limit. For the radiation distribution, the dependence of stability on is a bit obscure. If a scalar potential, function of the Brans-Dicke scalar field, is added to the action, the requirement of an infinite for stability is relaxed for a matter distribution with a nonzero trace whereas it becomes a possibility for a radiation distribution.
1 More- Received 20 September 2016
DOI:https://doi.org/10.1103/PhysRevD.95.064048
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