According to previous work, topological defects expand exponentially without an end if the vacuum expectation value of the Higgs field is of the order of the Planck mass. We extend the study of inflating topological defects to the Brans-Dicke gravity. With the help of numerical simulation we investigate the dynamics and spacetime structure of a global monopole. Contrary to the case of the Einst...

Gravitational field of a nonstatic global string has been studied in the context of Brans-Dicke theory of gravity. Both the metric components and the BD scalar field are assumed to be nonseparable functions of time and space.The spacetime may or may not have any singularity at a finite distance from the string core but the singularity at a particular time always remains. It has been shown that ...

We give here the calculation of density perturbations in a gravitation theory with a scalar field non-minimally coupled to gravity, i.e., the Brans-Dicke Theory of gravitation. The purpose is to show the influence of this scalar field on the dynamic behaviour of density perturbations along the eras where the equation of state for the matter can be put under the form p = αρ, where α is a constan...

For the last few decades, it is generally believed that after a (small) period of inflationary era (when the universe was accelerated) the universe has been evolving in a Big bang scenario (deceleration of the universe) and most of the present day observations are in accord with this cosmological model (known as Standard Cosmological Model). But difficulty has started when recent data from high...

We use the technique of conformal transformations to generate self-similar collapse in Brans-Dicke theory. We analyze the solutions concerning the critical behavior found recently by Choptuik. The critical exponent associated to the formation of black hole for near critical evolution is obtained. The role of the coupling parameter is discussed.

Extensions of Einstein gravity which allow the gravitational constant G to change with time as the universe evolves may provide a resolution to the horizon problem without invoking a period of vacuum domination and without the subsequent entropy violation. In a cosmology for which the gravitational constant is not in fact constant, the universe may be older at a given temperature than in a stan...