Related papers: Quintessence as k-essence
The accelerated expansion of the universe demands presence of an exotic matter, namely the dark energy. Though the cosmological constant fits this role very well, a scalar field minimally coupled to gravity, or quintessence, can also be…
This paper is devoted to the investigation of modified Chaplygin gas model in the context of solvable k-essence cosmologies. For this purpose, we construct equations of state parameter of this model for some particular values of the…
Astrophysical observations are pointing out huge amounts of dark matter and dark energy needed to explain the observed large scale structures and cosmic accelerating expansion. Up to now, no experimental evidence has been found, at…
We show that the combination of a fluid with a bulk dissipative pressure and quintessence matter can simultaneously drive an accelerated expansion phase and solve the coincidence problem of our current Universe. We then study some scenarios…
Recent cosmological and astrophysical observations point out that the Universe is in accelerating expansion and filled up with non-luminous matter. In order to explain the observed large scale structures and this accelerating behavior one…
K-essence Lagrangian is studied in the context of an early universe epoch when time is very small. Equation of state parameter as well as deceleration parameter , indicates an accelerated expansion of the universe at an early epoch of time…
The origin of the dark energy which is assumed to be responsible for the observed accelerated expansion of the universe still remains a scientific dilemma. Here we propose a tentative origin for this energy, if it is coming from a…
Based on the work of ratio gravity developed in 2018, which postulates the deformation of the cross ratio to associate with the physical model of gravity, we develop a mechanism to generate dynamical dark energy - a quintessence field…
We discuss some cosmological consequences of a general model of coupled quintessence in which the phenomenological coupling between the cold dark matter and dark energy is a function of the cosmic scale factor $\epsilon(a)$. This class of…
A dependence of the neutrino masses on the dark energy scalar field could provide a solution to the why now problem of dark energy. The dynamics of the resulting cosmological model, growing neutrino quintessence, include an attractive force…
Dynamical vacuum energy or quintessence, a slowly varying and spatially inhomogeneous component of the energy density with negative pressure, is currently consistent with the observational data. One potential difficulty with the idea of…
The origin of accelerating expansion of the Universe is one the biggest conundrum of fundamental physics. In this paper we review vacuum energy issues as the origin of accelerating expansion - generally called dark energy - and give an…
Observational evidence indicating that the expansion of the universe is accelerating has surprised cosmologists in recent years. Cosmological models have sought to explain this acceleration by incorporating `dark energy', of which the…
The generation of a kination-dominated phase by a quintessential exponential model is investigated and the parameters of the model are restricted so that a number of observational constraints (originating from nucleosynthesis, the present…
In this paper, dark energy is modelled via a spherically symmetric quintessence scalar field $\varphi$, the dynamics of which are found to be analogous to a pendulum. This is due to a driving axion potential $V(\left|\varphi\right|)$, whose…
We discuss the electroweak quintessence axion as a candidate for dark energy, taking into account observational as well as quantum-gravity constraints.
Two mechanisms by which the Quintessence scalar could enhance the relic abundance of dark matter particles are discussed. This effect can have an impact on supersymmetric candidates for dark matter.
With a parametric form of the equation of state parameter of dark energy, a quintessence potential has been reconstructed. The potential is found to be a generalization of a double exponential potential. The constraints on the parameters…
The recent observations support that our universe is flat and expanding with acceleration. A quintessence model with a general relation between the quintessence potential and the quintessence kinetic energy was proposed to explain the…
It is suggested that the apparently disparate cosmological phenomena attributed to so-called 'dark matter' and 'dark energy' arise from the same fundamental physical process: the emergence, from the quantum level, of spacetime itself. This…