Related papers: Interpreting Dark Energy Data Away from $\Lambda$
Considering that the universe is filled with the nonrelativistic matter and dark energy and each component is respectively satisfied with its conservation condition in the absence of their interaction, we give the change rate of the…
In order to solve the fine-tuning problem of the cosmological constant, we propose a simple model with the vacuum energy non-minimally coupled to the inflaton field. In this model, the vacuum energy decays to the inflaton during…
Perhaps the deepest mystery of our accelerating Universe in expansion is the existence of a tiny and rigid cosmological constant, $\Lambda$. Its size is many orders of magnitude below the expected one in the standard model of particle…
We confront two types of phantom dark energy potential with observational data. The models we consider are the power-law potential, $V\propto {\phi}^{\mu}$, and the exponential potential, $V\propto \exp({\lambda}{\phi}/{M_P})$. We fit the…
Recently a lot of attention has been given to building dark energy models in which the equation-of-state parameter $w$ can cross the phantom divide $w=-1$. However, to our knowledge, these models with crossing the phantom divide only…
The dark energy crossing of the cosmological constant boundary (the transition between the quintessence and phantom regimes) is described in terms of the implicitly defined dark energy equation of state. The generalizations of the models…
Recent determinations of the equation of state of dark energy hint that this may well be of the phantom type, i.e., $w_{de} < -1$. If confirmed by future experiments, this would strongly point to the existence of fields that violate the…
A dark energy component is responsible for the present stage of acceleration of our universe. If no fine tuning is assumed on the dark energy potential then it will end up dominating the universe at late times and the universe will not stop…
The non-relativistic self-gravitating gas in thermal equilibrium in the presence of a positive cosmological constant Lambda (dark energy) is investigated. The dark energy introduces a force pushing outward all particles with strength…
A model of holographic dark energy with an interaction with matter fields has been investigated. Choosing the future event horizon as an IR cutoff, we have shown that the ratio of energy densities can vary with time. With the interaction…
Dark energy is an elusive concept, which has been introduced two decades ago in order to make the acceleration of the universe a comprehensible phenomenon. However, the nature of this energy is far from being understood, both from a…
Cosmological observations strongly suggest the presence of dark energy which comprises the majority of the current energy density of the universe. The equation of state relating the pressure and energy density of this dark energy, p = w…
We study the cosmology with the running dark energy. The parametrization of dark energy with the respect to the redshift is derived from the first principles of quantum mechanics. Energy density of dark energy is obtained from the quantum…
It was first observed at the end of the last century that the universe is presently accelerating. Ever since, there have been several attempts to explain this observation theoretically. There are two possible approaches. The more…
A cosmological constant, Lambda, is the most natural candidate to explain the origin of the dark energy (DE) component in the Universe. However, due to experimental evidence that the equation of state (EOS) of the DE could be evolving with…
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…
The discovery of accelerated Hubble expansion in the SNIa data and the observed power spectrum of the microwave background radiation provide an ample support for Dark energy and Dark matter. Except for the so far well-known facts that cold…
A pressureless dark matter component fits well with several cosmological observations. However, there are indications that cold dark matter may encounter challenges in explaining observations at small scales, particularly at galactic…
Recently the Dark Energy Survey (DES) Collaboration presented evidence that the equation of state $w$ of the dark energy is varying, or $w \simeq -0.948$ if it is constant. In either case, the dark energy cannot be due to a cosmological…
We extract key information of dark energy from current observations of BAO, OHD and $H_0$, and find hints of dynamical behaviour of dark energy. In particular, a dynamical dark energy model whose equation of state crosses $-1$ is favoured…