Related papers: Talk about Pivots
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…
Determining the mechanism behind the current cosmic acceleration constitutes a major question nowadays in theoretical physics. If the dark energy route is taken, this problem may potentially bring to light new insights not only in Cosmology…
We combine cosmic chronometer and growth of structure data to derive the redshift evolution of the dark energy equation of state $w$, using a novel agnostic approach. The background and perturbation equations lead to two expressions for…
The dark energy models with variable equation of state parameter $\omega$ is investigated by using law of variation of Hubble's parameter that yields the constant value of deceleration parameter. The equation of state parameter $\omega$ is…
We study a correspondence between $f(R)$ model of gravity and a phenomenological kind of dark energy (DE), which is known as QCD ghost dark energy. Since this kind of dark energy is not stable in the context of Einsteinian theory of gravity…
We give a scalar field description of two dark energy parameterizations, and we analyze in detail its cosmology both at the level of background evolution and at the level of linear perturbations. In particular, we compute the statefinder…
We study dynamical dark energy models within Einstein's theory by means of matter perturbations and the growth index $\gamma$. Within four-dimensional General Relativity, we assume that dark energy does not cluster, and we adopt a linear…
Confirmation of accelerated expansion of the universe probed the concept of dark energy theory, and since then, numerous models have been introduced to explain its origin and nature. The present work is based on reconstructing dark energy…
Dark energy affects the CMB through its perturbations and affects both CMB and Sn-Ia through its background evolution. Using recent CMB and Sn-Ia data sets, together with the most general parameterization of the dark energy equation of…
To reconstruct dark energy models the redshift $z_{eq}$, marking the end of radiation era and the beginning of matter-dominated era, can play a role as important as $z_{t}$, the redshift at which deceleration parameter experiences a…
We investigate the value of future dark energy experiments by modeling their ability to constrain the dark energy equation of state. Similar work was recently reported by the Dark Energy Task Force (DETF) using a two dimensional…
The satellite experiment WMAP has produced for the first time a high-coverage, high resolution survey of the microwave sky, releasing publicly available data that are likely to remain unrivalled for years to come. Here we compare the WMAP…
Dynamical models for dark energy are an alternative to the cosmological constant. It is important to investigate properties of perturbations in these models and go beyond the smooth FRLW cosmology. This allows us to distinguish different…
The DESI collaboration have recently analyzed their first year of data, finding a preference for thawing dark energy scenarios when using parameterized equations of state for dark energy. We investigate whether this preference persists when…
I consider some of the issues we face in trying to understand dark energy. Huge fluctuations in the unknown dark energy equation of state can be hidden in distance data, so I argue that model-independent tests which signal if the…
I briefly review our current understanding of dark matter and dark energy. The first part of this paper focusses on issues pertaining to dark matter including observational evidence for its existence, current constraints and the `abundance…
Recently, a novel equation of state (EoS) parameter for dark energy has been introduced which deals with a special mathematical function, known as the Lambert$W$ function. In this paper, we study the effect on the growth of perturbations…
It may be determined by non-parametric method if the dark energy evolves with time. We propose a method of combining PCA and biased estimation on the basis of ridge regression analysis to reconstruct parameters, meanwhile we present an…
We investigate the restrictions on the equation-of-state parameter of phantom cosmology, due to the minimum quantum gravitational requirements. We find that for all the examined $w_\Lambda(z)$-parametrizations and for arbitrary phantom…
We place, by the maximum likelihood method, constraints on a variable dark energy model with the equation of state $w=w_0/[1+b\ln (1+z)]^2$ using some recent observational data, including the new Sne Ia data from the SNLS, the size of…