Related papers: Finite scale factor and future singularities
This paper deals with dark and phantom energy in the tachyon and sub-quantum models for dark energy. We obtain that the simplest condition for such a regime to occur in these scenarios is that the scalar field be Wick rotated to imaginary…
We investigate the consequences of an imperfect dark energy component on the large scale structure. A phenomenological three parameter fluid description is used to study the effect of dark energy on the cosmic microwave background radiation…
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.…
We study the possibility that dark energy decays in the future and the universe stops accelerating. The fact thatthe cosmological observations prefer an equation of state of dark energy smaller than -1 can be a signal that dark energy will…
We find an explicit cosmological model which allows a special type of cosmological singularity which we call a $w$-singularity. This singularity has the scale factor finite, the energy density and pressure vanishing, and the only singular…
In this article, we examine a model which proposes a common explanation for the presence of additional attractive gravitational effects -- generally considered to be due to dark matter -- in galaxies and in clusters, and for the presence of…
A set of temporal singularities (transients) in the mass-energy density and pressure, bearing a specific mathematical structure which represents a new solution to the continuity equation (\ie~conservation of mass-energy) and satisfying the…
We consider finite-time, future (sudden or Big Rip type) singularities which may occur even when strong energy condition is not violated but equation of state parameter is time-dependent. Recently, example of such singularity has been…
We discuss the recently suggested Ricci-Gauss-Bonnet holographic dark energy in Chern-Simons modified gravity. We have tested some general forms of the scale factor $a(t)$, and used two physically reasonable forms which have been proved to…
Classical models for dark energy can exhibit a variety of singularities, many of which occur for scale factors much bigger than the Planck length. We address here the issue whether some of these singularities, the big freeze and the big…
The paper deals with Bianchi type V Universe, which has dynamical energy density. We consider Bianchi type V space-time, introducing three different skewness parameters along spatial directions to quantify the deviation of pressure from…
The four-dimensional Friedman flat universe, filled with an ideal fluid with a linear (oscillating) inhomogeneous equation of state (EoS) depending on time, is studied. The equations of motion are solved. It is shown that in some cases…
In this note, we investigate the stability of the dark energy model from time crystals proposed in [1]. We emphasize two ingredients, the coupling of the scalar field to gravity, and the fact that these time crystals are on an expanding FRW…
Dark energy dynamics in the recent universe is influenced by its evolution through the long, matter dominated expansion history. A particular dynamical property, the flow variable, remains constant in several classes of scalar field models…
The present accelerated expansion of the universe has enriched the list of possible scenarios for its fate, singular or not. In this paper a unifying framework for analyzing such behaviors is proposed, based on generalized power and…
We investigate models of future finite-time singularities in $f(T)$ theory, where $T$ is the torsion scalar. The algebraic function $f(T)$ is put as the teleparallel term $T$ plus an arbitrary function $g(T)$. A suitable expression of the…
We propose a model for an anisotropic dark energy star where we assume that the radial pressure exerted on the system due to the presence of dark energy is proportional to the isotropic perfect fluid matter density. We discuss various…
We investigate the clustering properties of a dynamical dark energy component. In a cosmic mix of a pressureless fluid and a light scalar field, we follow the linear evolution of spherical matter perturbations. We find that the scalar field…
By studying first a new decelerating sudden future singularity (SFS) universe we report finding a novel type of cosmological singularity which we dub a finite time pseudo-rip (FTPR) because unlike for a pseudo-rip, it happens in the finite…
We examine phantom dark energy models derived from a scalar field with a negative kinetic term for which V(phi) approaches infinity asymptotically. All such models can be divided into three classes, corresponding to an equation of state…