The spectra of relic gravitational waves produced as a result of cosmological expansion of the inflationary models are derived in Brans-Dicke (BD)theory of gravity.The time dependence of the very early Hubble parameter and matter energy density are derived from frequency dependent spectrum of relic gravitational waves.Also it is found that Brans-Dicke scalar field contributes to the energy dens...

We study spherically symmetric solutions to the Jordan-Brans-Dicke field equations under the assumption that the space-time may possess an arbitrary number of spatial dimensions. Assuming a perfect fluid with the equation of state p = ερ, we show that there are static interior nontrivial solutions in three dimensional Jordan-Brans-Dicke gravity theory.

We have solved Cosmological Gravitational Wave(GW) equation in the frame work of Gen-eralised Brans-Dicke(GBD) theory for all epochs of the Universe.The solutions are expresed in terms of the present value of the Brans-Dicke coupling parameter ω(φ).It is seen that the solutions represent travelling growing modes for negative values of ω 0 for all epochs of the Universe.

We show how conformal relativity is related to Brans–Dicke theory and to low-energy-effective superstring theory. Conformal relativity or the Hoyle–Narlikar theory is invariant with respect to conformal transformations of the metric. We show that the conformal relativity action is equivalent to the transformed Brans–Dicke action for ω = −3/2 (which is the border between standard scalar field an...

In this paper it is shown that in Brans Dicke theory, if one considers a non-minimal coupling between the matter and the scalar field, it can give rise to a late time accelerated expansion for the universe preceded by a decelerated expansion for very high values of the Brans Dicke parameter ω.

The standard tenet that Brans–Dicke theory reduces to general relativity in the ω → ∞ limit has been shown to be false when the trace of the matter energy– momentum tensor vanishes. The issue is clarified in a new approach and the asymptotic behaviour of the Brans–Dicke scalar is rigorously derived. To appear in Physics Letters A

We studied the Einstein-Brans-Dicke cosmology in detail. The difference of the evolution of the universe is significant between Einstein-Brans-Dicke cosmology and standard big-bang model during the radiation-dominated era. The power-law evolution of the scale factor is fast enough to solve the cosmological puzzles and slow enough to avoid the graceful exit problem. However, the constraints from...

We present the static, spherically symmetric solutions of the low energy d = 4 string. They form a simple generalisation of the Schwarzschild solution and describe the gravitational field of a spherical star in perturbative string theory. If the Robertson parameter γ is different from one, these solutions describe singular objects with naked singularities at their horizons, and whose Hawking te...

We investigate the stability of a family of spherically symmetric static solutions in vacuum Brans-Dicke theory ~with v50) recently described by van Putten. Using linear perturbation theory, we find one exponentially growing mode for every member of the family of solutions, and thus conclude that the solutions are not stable. Using a previously constructed code for spherically symmetric Brans-D...