In the present work, the gravitational field of superconducting cosmic string has been investigated in the context of Brans-Dicke theory of gravity. We have presented two kind of solutions for the spacetime in the far field zone of the string. When the B-D scalar field is switched off, one of the solutions reduces to the solution earlier obtained by Moss and Poletti in General Relativity. e-mai...

In this paper it is shown that in Brans-Dicke (BD) theory, if one considers a non-minimal coupling between the matter and scalar field, it can give rise to a bouncing universe (i.e. an expanding universe preceded by a contracting universe). Two examples of such universes have been considered in a spatially flat FRW universe and their physical properties have been studied.

We study the cosmology of the Brans-Dicke theory with perfect fluid type matter. In our previous work [7], we found exact solutions for any BransDicke parameter ω and for general parameter γ of equation of state. In this paper we further study the cosmology of these solutions by analyzing them according to their asymptotic behaviors. The cosmology is classified into 19 phases according to the v...

Any quantum theory of gravity which treats the gravitational constant as a dynamical variable has to address the issue of superpositions of states corresponding to different eigenvalues. We show how the unobservability of such superpositions can be explained through the interaction with other gravitational degrees of freedom (decoherence). The formal framework is canonically quantized Jordan-Br...

This paper is devoted to obtaining a class of rotating black brane solutions of Brans–Dicke theory in the presence of a power Maxwell-invariant source. Since the field equations include the second derivatives of the scalar field, we cannot solve them, directly. Therefore, we first obtain the solutions of Einstein-dilaton gravity in the presence of a nonlinear Maxwell field, and then, by using a...

We develop a formalism for calculating cosmic microwave background (CMB) temperature and polarization anisotropies in cosmological models with BransDicke gravity. We then modify publicly available Boltzmann codes to calculate numerically the temperature and polarization power spectra. Results are illustrated with a few representative models. Comparing with the generalrelativistic model with the...