Related papers: Interpretation of bulk viscosity as the generalize…
In the current framework of Einstein's equations in general relativity (GR), gravity is described by the spacetime curvature. However, there are other descriptions where the origin of gravity can be understood through torsion and…
We consider the prospects for dark matter/energy unification in k-essence type theories. General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions. We develop an extension of the…
Although various cosmological observations congruously suggest that our universe is dominated by two dark components, the cold dark matter without pressure and the dark energy with negative pressure, the nature and origin of these…
The hypothesis that dark matter and dark energy are unified through the Chaplygin gas is reexamined. Using generalizations of the spherical model which incorporate effects of the acoustic horizon we show that an initially perturbative…
We present a simple higher dimensional FRW type of model where the acceleration is apparently caused by the presence of the extra dimensions. Assuming an ansatz in the form of the deceleration parameter we get a class of solutions some of…
Based on the assumption that the dark energy possessing bulk viscosity is homogenously and isotropically permeated in the universe, we propose three new viscous dark energy (VDE) models to characterize the accelerating universe. By…
The accelerating expansion of the universe is the most surprising cosmological discovery in many decades. In this short review, we briefly summarize theories for the origin of cosmic acceleration and the observational methods being used to…
We consider a cosmological model dominated by stiff fluid with a constant bulk viscosity. We classify all the possible cases of the universe predicted by the model and analyzing the scale factor, density as well as the curvature scalar. We…
This paper investigates regarding cosmological implications of a bulk viscous modified Chaplygin gas (MCG) in (2+1)-dimensional Friedmann-Robertson-Walker spacetime, incorporating both theoretical analysis and observational constraints. We…
Cosmic acceleration is explained quantitatively, as an apparent effect due to gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe. "Dark energy" is a misidentification of…
In this paper we are to study homogeneous and anisotropic Bianchi type-V universe in presence of bulk viscous fluid source of matter with time function gravitational constant G and cosmological term lambda. The viscosity coefficient is…
We find exact solution of the Einstein equations in the context of the brane world scenario. We have supposed a {generalized chaplygin gas} equation of state for bulk. This study display a constant energy density and pressure for bulk in…
Thermodynamic analyses of dark energy as a relativistic fluid indicates that this intriguing component of the universe mimics a bulk viscous pressure when the parameter of its barotropic equation of state varies with time. Since in…
The Chaplygin gas has been proposed as a possible dark energy, dark matter candidate. As a working fluid in a Friedmann-Robertson-Walker universe, it exhibits early behavior reminiscent of dark matter, but at later times is more akin to a…
We explore the idea that cosmic acceleration may be a byproduct of late-time effects like structure formation in two steps. First, we consider the equation of state for an inhomogeneous cosmic fluid, which may lead to a Gedanken-model for…
We study the late-time cosmological dynamics of a spatially flat FLRW universe in the framework of $f(Q)$ gravity, where $Q$ denotes the nonmetricity scalar. The matter sector is modeled as a bulk viscous fluid with a free equation-of-state…
In this paper, we investigate cosmological consequences of a scenario for recently reported accelerated expansion of the Universe, in which the generalized Chaplygin gas (GCG) along with the baryonic matter are responsible for this observed…
Viscous GCG(generalized Chaplygin gas) cosmology is discussed, assuming that there is bulk viscosity in the barotropic fluid and GCG. The dynamical analysis indicates that the phase…
Observations suggest that nearly seventy per cent of the energy density in the universe is unclustered and exerts negative pressure. Theoretical understanding of this component (`dark energy'), which is driving an accelerated expansion of…
Neutrinos coupled to an underlying scalar field in the scenario for unification of mass varying dark matter and cosmon-{\em like} dark energy is examined. In the presence of a tiny component of mass varying neutrinos, the conditions for the…