相关论文: Unified Dark Fluid with Constant Adiabatic Sound S…
A model of unification of dark matter and dark energy based on the modeling of the speed of sound as a function of the parameter of the equation of state is introduced. It is found that the model in which the speed of sound depends on the…
The characterisation of dark energy is one of the primary goals in cosmology especially now that many new experiments are being planned with the aim of reaching a high sensitivity on cosmological parameters. It is known that if we move away…
In this paper, we test the spherical collapse of a viscous unified dark fluid (VUDF) which has constant adiabatic sound speed and show the nonlinear collapse for VUDF, baryons, and dark matter which are important to form the large scale…
The standard model of cosmology relies on the existence of two components, "dark matter" and "dark energy", which dominate the expansion of the Universe. There is no direct proof of their existence, and their nature is still unknown. Many…
We show that the observed rotation curves of spiral galaxies constrain the sound speed of the dark matter to be $c_s < 10^{-4} c$, where $c$ is the speed of light in vacuum. Using the Modified Chaplygin Gas as a representative example of a…
The Cold Dark Matter (CDM) model, wherein the dark matter is treated as a pressureless perfect fluid, provides a good fit to galactic and cosmological data. With the advent of precision cosmology, it should be asked whether this simplest…
As observational evidence increasingly consolidates the case for a cosmological constant being the source of the Universe's accelerated expansion, the question whether, and if so, how well, future experiments could detect deviations from…
Considering the general Lagrangian of k-essence models, we study and classify them through variables connected to the fluid equation of state parameter w_\kappa. This allows to find solutions around which the scalar field describes a…
We consider a 5-dimensional Ricci flat bouncing cosmological model in which the 4-dimensional induced matter contains two components at late times - the cold dark matter (CDM)+baryons and dark energy. We find that the arbitrary function…
Some dark energy cosmological models are constructed in the framework of a generalised Brans-Dicke theory which contains a self interacting potential and a dynamical coupling parameter. The dark sector of the universe is considered through…
It is well known that, in the context of general relativity, an unknown kind of matter that must violate the strong energy condition is required to explain the current accelerated phase of expansion of the Universe. This unknown component…
The rate of structure formation in the Universe is different in homogeneous and clustered dark energy models. The degree of dark energy clustering depends on the magnitude of its effective sound speed $c^{2}_{\rm eff}$ and for $c_{\rm…
Constantly accumulating observational data continue to confirm that about 70% of the energy density today consists of dark energy responsible for the accelerated expansion of the Universe. We present recent observational bounds on dark…
The evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with perfect fluid and dark energy components is studied by generalizing the recent results…
Based on superfluid behavior of a (boson) dark matter as the light itself, a unified model for dark matter and quintessence is proposed. Inspired by (O'Dell et al. 2000) which in an exciting study showed that particular configurations of…
We review the hydrodynamics of the dark sector components in Cosmology. For this purpose we use the approach of Newtonian gravitational instability, and thereafter we add corrections to arrive to a full relativistic description. In…
A recently proposed Dynamical Space-time Cosmology (DSC) that unifies dark energy and dark matter is studied. The general action of this scenario includes a Lagrange multiplier, which is coupled to the energy momentum tensor and a scalar…
We consider a unified model of interacting dark matter and dark energy to account for coincidence of present day dark energy and dark matter densities. We assume dark energy to be represented by a homogeneous scalar field $\phi$ whose…
Dark matter and dark energy are essential in the description of the late Universe, since at least the epoch of equality. On the other hand, the inflation is also necessary and demands a "dark" component, usually associated to a scalar field…
In this manuscript, we present a novel dark energy model to study the nature of dark energy. Non-extensive Kaniadakis entropy and, timescale as infrared cutoff are the major tools of the current study. Age of the Universe will serve the…