相关论文: Large Dynamical System Analysis for Anisotropic Un…
We investigate a cosmological solution within the framework of a 5D standing wave braneworld model generated by gravity coupled to a massless scalar phantom-like field. By obtaining a full exact solution of the model we found a novel…
In this paper, we study the phase space of cosmological models in the context of Einstein-Gauss-Bonnet theory. More specifically, we consider a generalized dynamical system that encapsulates the main features of the theory and for the cases…
We study the Brans-Dicke model in the presence of an axion. The dynamical equations are solved when the fields are space independent and the metric is spatially flat. It is found that at late time the scale factor undergoes decelerated…
We discuss the general framework for a perfect continuum medium in cosmology and show that an interesting generalization of the fluids normally used is for the medium to have rigidity and, hence, be analogous to an elastic solid. Such…
We explore a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) universe which is filled with agegraphic dark energy (ADE) with mutual interaction with pressureless dark matter in the background of Brans-Dicke (BD) theory.…
In this paper, we study Friedmann cosmology with time-varying vacuum energy density in the context of Brans-Dicke theory. We consider an isotropic and homogeneous flat space, filled with a matter-dominated perfect fluid and a dynamical…
Considering a spherically-symmetric non-static cosmological flat model of Robertson-Walker universe we have investigated the problem of perfect fluid distribution interacting with the gravitational field in presence of massive scalar field…
Following recent considerations of a non-zero value for the vacuum energy density and the realization that a simple Kantowski-Sachs model might fit the classical tests of cosmology, we study the qualitative behavior of three anisotropic and…
In this paper, we investigate the background dynamics in brane cosmology when dark energy is coupled to dark matter by a suitable interaction. Here we consider an homogeneous and isotropic Friedmann-Robertson-Walker (FRW) brane model and…
We show that the introduction of a hyperbolic phase for Brans-Dicke (BD) field results in a flat vacuum cosmological solution of Hubble parameter H and fractional rate of change of BD scalar field, F which asymptotically approach constant…
We show that the scalar-vacuum Brans-Dicke equations in 5D are equivalent to Brans-Dicke theory in 4D with a self interacting potential and an effective matter field. The cosmological implication, in the context of FRW models, is that the…
The dynamical realisation of the equation of state $p +\rho =0$ is studied. A non-pathological dynamics for the perturbations of such a system mimicking a dynamical cosmological constant (DCC) requires to go beyond the perfect fluid…
We consider a dynamical systems formulation for models with an exponential scalar field and matter with a linear equation of state in a spatially flat and isotropic spacetime. In contrast to earlier work, which only considered linear…
The accelerated expansion of the universe together with its present day isotropy has posed an interesting challenge to the numerous model theories presented over the years to describe them. In this paper, we address the above questions in…
Five-dimensional cosmological models with two 3-branes and with a buck cosmological constant are studied. It is found that for all the three cases ($\Lambda =0$, $\Lambda >0$, and $\Lambda <0$), the conventional space-time singularity ``big…
We study in detail the phase space of a Friedmann-Robertson-Walker Universe filled with various cosmological fluids which may or may not interact. We use various expressions for the equation of state, and we analyze the physical…
Dynamical systems methods are used to investigate global behavior of the spatially flat Friedmann-Robertson-Walker cosmological model in gravitational theory with a non-minimally coupled scalar field and a constant potential function. We…
The Standard Cosmological Model assumes that the Universe is, on average, homogeneous and isotropic for large scales (z>1), but this principle has been questioned from the results about Cosmic Microwave Background. This radiation has…
We present a brief review of the modified Brans-Dicke theory (MBDT) in arbitrary dimensions, whereby the ($N+1$)-dimensional field equations reduce to the $N$-dimensional $(ND)$ configuration with sources and an effective induced scalar…
In this paper we investigate a Bianchi type I transitioning Universe in Brans-Dicke theory. To get an explicit solution of the field equations, we assume scalar field as $\phi = \phi_{0}\left[t^{\alpha}exp(\beta t)\right]^{\delta}$ with…