Related papers: Viscous dark energy and phantom evolution
We investigate cosmological models with two interacting fluids: dark energy and dark matter in flat Friedmann-Robertson-Walker universe. The interaction between dark energy and dark matter is described in terms of the parameters present in…
Models of the universe with arbitrary (non gravitational) interaction between the components of the cosmic fluid: the phantom energy and the background, are investigated. A general form of the interaction that is inspired in scalar-tensor…
The discovery of accelerated cosmic expansion implies that, in addition to the attractive gravity of matter, there exists in our universe some other form of energy (dark energy or cosmological constant) producing a repulsive force. The…
A bulk viscosity is introduced in the formalism of modified gravity. It is shown that, on the basis of a natural scaling law for the viscosity, a simple solution can be found for quantities such as the Hubble parameter and the energy…
Cosmological models with an inhomogeneous viscous dark fluid, coupled with dark matter in the Friedmann- Robertson-Walker (FRW) flat universe, are considered. The influence of thermal effects caused by Hawking radiation on the visible…
The physical nature of the presently dominating enigmatic dark energy in the expanding universe is demonstrated to be explainable as an excess of the kinetic energy with respect to its potential energy. According to traditional Friedman…
Quantum corrections coming from massless fields conformally coupled with gravity are studied, in order to see if they can lead to avoidance of the annoying Big Rip singularity which shows up in a flat Friedmann-Robertson-Walker universe…
The cosmological observations suggest that the presently accelerating universe should be filled by an exotic form of matter, violating the strong energy condition, of unknown nature and origin. We propose the viscous dark matter of a source…
We investigate the effects of viscosity terms depending on the Hubble parameter and its derivatives in the dark energy equation of state. Such terms are possible if dark energy is a fictitious fluid originating from corrections to the…
We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time,…
This paper contains a detailed discussion on new cosmic solutions describing the early and late evolution of a universe that is filled with a kind of dark energy that may or may not satisfy the energy conditions. The main distinctive…
The present study deals with dissipative future universe without big rip in context of Eckart formalism. The generalized chaplygin gas, characterized by equation of state $p=-\frac{A}{\rho^\frac{1}{\alpha}}$, has been considered as a model…
We study the evolution of a flat Friedmann-Robertson- Walker Universe, filled with a bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The dimensional analysis of the model suggest a…
We review the several models of the dark energy, which may generate the accelerated expansion of the present universe. We also discuss the the Big Rip singularity, which may occur when the equation of the state parameter w is less than -1.…
A cosmological model with an inhomogeneous viscous dark fluid coupled with dark matter in a flat Friedman-Robertson-Walker universe is investigated. The influence of dark matter on the behavior of an inhomogeneous viscous fluid of this…
We propose a new model for the viscosity of cosmic matters, which can be applied to different epochs of the universe. Using this model, we include the bulk viscosities as practical corrections to the perfect fluid models of the baryonic and…
We extend the Loop Quantum Cosmology matter bounce scenario in order to include a dark energy era, which ends abruptly at a Rip singularity where the scale factor and the Hubble rate diverge. In the "deformed matter bounce scenario", the…
We study effects of viscous fluid coupled with dark matter in our universe. We consider bulk viscosity in the cosmic fluid and we suppose the existence of a coupling between fluid and dark matter, in order to reproduce a stable de Sitter…
We present a discussion of the effects induced by bulk viscosity on the very early Universe stability. The viscosity coefficient is assumed to be related to the energy density $\rho$ via a power-law of the form $\zeta=\zeta_0 \rho^s$ (where…
We examine in more detail specific models which yield a little rip cosmology, i.e., a universe in which the dark energy density increases without bound but the universe never reaches a finite-time singularity. We derive the conditions for…