相关论文: Evolution of Generalized Brans-Dicke parameter wit…
We report strong cosmological constraints on the Brans-Dicke (BD) theory of gravity using Cosmic Microwave Background data from Planck.We consider two types of models. First, the initial condition of the scalar field is fixed to give the…
We show that Friedmann-Robertson-Walker (FRW) geometry with flat spatial section in quantized (Wheeler deWitt quantization) Brans Dicke (BD) theory reveals a rich phase structure owing to anomalous breaking of a classical symmetry, which…
We develop a model for the evolution of economic entities within a geographical type of framework. On a square symmetry lattice made of three (economic) regions, firms, described by a scalar fitness, are allowed to move, adapt, merge or…
In this paper, we investigate a scalar field Brans-Dicke cosmological model in Lyra's geometry which is based on the modifications in geometrical term as well as energy term of Einstein's field equations. We have examined the validity of…
We consider a generalized Brans-Dicke model in which the scalar field has a self-interacting potential function. The scalar field is also allowed to couple non-minimally with the matter part. We assume that it has a chameleon behavior in…
We study the averaged action of the Randall-Sundrum model with a time dependent metric ansatz. It can be reformulated in terms of a Brans-Dicke action with time dependent Newton's constant. We show that the physics of early universe,…
In a Brans-Dicke (BD) cosmological model, the energy density associated with some scalar field decreases as $\displaystyle a^{{-2}(\frac{\omega_{o}+ {\frac12}%}{\omega_{o}+1})} $ with the scale factor $a(t)$ of the Universe, giving a matter…
Persistent evidence for a cosmic hemispherical asymmetry in the temperature field of cosmic microwave background (CMB) as observed by both WMAP as well as PLANCK increases the possibility of its cosmological origin. Presence of this signal…
A conformal transformation of a static or stationary spacetime by a time dependent conformal scale factor ${S(\tau )}^2$ is one of the methods of producing a cosmological spacetime. Using this knowledge and Brans-Dicke (BD) field equations,…
Recently, interesting braneworld cosmologies in the Randall-Sundrum scenario have been constructed using a bulk spacetime which corresponds to a charged AdS black hole. In particular, these solutions appear to `bounce', making a smooth…
The evolution of the cosmological perturbations is studied in the context of the Randall-Sundrum brane world scenario, in which our universe is realized on a three-brane in the five dimensional Anti-de Sitter(AdS) spacetime. We develop a…
We investigate observational constraints on the Brans-Dicke cosmological model using observational data coming from distant supernovae type Ia, the Hubble function $H(z)$ measurements, information coming from the Alcock-Paczy{\'n}ski test,…
Anisotropic spherically symmetric solutions within the framework of the Brans-Dicke theory are uncovered through a unique gravitational decoupling approach involving a minimal geometric transformation. This transformation effectively…
It has been shown that Brans-Dicke (BD) theory in anisotropic cosmological model can alone solve the quintessence problem and we have accelerated expanding universe without any quintessence matter. Also the flatness problem has been…
We numerically study the dual field theory evolution of five-dimensional asymptotically anti-de Sitter solutions of supergravity that develop cosmological singularities. The dual theory is an unstable deformation of the N = 4 gauge theory…
Based on the idea that the components of a cosmological metric may be determined by the total gravitational potential of the universe, the scalar field $\phi=1/G$ in the Jordan-Brans-Dicke (JBD) theory is introduced as evolving with the…
We present a reformulation of quantum adiabatic theory in terms of an emergent electromagnetic framework, emphasizing the physical consequences of geometric structures in parameter space. Contrary to conventional approaches, we demonstrate…
We consider bouncing cosmologies in which an ekpyrotic contraction phase with w >> 1 is followed by a bouncing phase with w < -1 that violates the null energy condition. The bouncing phase, induced by ghost condensation, is designed to…
We consider Brans-Dicke theory with a self-interacting potential in Einstein conformal frame. We show that an accelerating expansion is possible in a spatially flat universe for large values of the Brans-Dicke parameter consistent with…
The Brans-Dicke model with a variable cosmological term ($BD\Lambda$) has been investigated with use of the coupling constant of $\omega=10^4$. Parameters inherent in this model are constrained from comparison between Big Bang…