Related papers: The Little Rip
We investigate various dark energy models by taking into account the thermal effects induced from Hawking radiation on the apparent horizon of the Universe, for example near a finite-time future singularity. If the dark energy density…
In this work we consider a family of cosmological models featuring future singularities. This type of cosmological evolution is typical of dark energy models with an equation of state violating some of the standard energy conditions (e.g.…
Recently it was found, in a broad class of models, that the dark energy density may change its sign during the evolution of the universe. This may lead to a global collapse of the universe within the time t_c ~ 10^{10}-10^{11} years. Our…
We present an analytical fit to the growth function of the dark matter perturbations when dark energy perturbations are present. The growth index depends upon the dark energy equation of state w, the speed of sound of the dark energy…
Traditionally, inflationary models are analyzed in terms of parameters such as the scalar spectral index ns and the tensor to scalar ratio r, while dark energy models are studied in terms of the equation of state parameter w. Motivated by…
We have reanalysed constraints on the equation of state parameter, w_Q = P/rho, of the dark energy, using several cosmological data sets and relaxing the usual constraint w_Q > -1. We find that combining Cosmic Microwave Background, large…
A model-independent method to study the possible evolution of dark energy is presented. Optimal estimates of the dark energy equation of state w are obtained from current supernovae data from Riess et al. (2004) following a principal…
The background cosmological dynamics of the late Universe is analysed on the framework of a dark energy model described by an holographic Ricci dark energy component. Several kind of interactions between the dark energy and the dark matter…
We report the constraints on the dark energy equation-of-state w(z) using the latest 'Constitution' SNe sample combined with the WMAP5 and SDSS data. Based on the localized principal component analysis and the model selection criteria, we…
The Weakly Interacting Massive Particles(WIMPs) have long been the favored CDM candidate in the standard $\Lambda$CDM model. However, owing to great improvement in the experimental sensitivity in the past decade, some parameter space of the…
Theories of evolving quintessence are constructed that generically lead to deviations from the w = -1 prediction of non-evolving dark energy. The small mass scale that governs evolution, m_\phi \approx 10^{-33} eV, is radiatively stable,…
Detecting dark energy dynamics is the main quest of current dark energy research. Addressing the issue demands a fully consistent analysis of CMB, large scale structure and SN-Ia data with multi-parameter freedom valid for all redshifts.…
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…
A possible solution to the dark energy problem is that Einstein's theory of general relativity is modified. A suite of models have been proposed that, in general, are unable to predict the correct amount of large scale structure in the…
We consider General Relativity with matter, radiation and a minimally coupled dark energy defined by an equation of state w. Using dynamical system method, we find the equilibrium points of such a theory assuming an expanding Universe and a…
We present new constraints on the evolution of dark energy from an analysis of Cosmic Microwave Background, supernova and X-ray galaxy cluster data. Our analysis employs a minimum of priors and exploits the complementary nature of these…
Collisionless, cold dark matter in the form of weakly-interacting massive particles (WIMPs) is well-motivated in particle physics, naturally yields the observed relic density, and successfully explains structure formation on large scales.…
A cosmology with the growing cosmological term is considered. If there is no exchange of energy between vacuum and matter components, the requirement of general covariance implies the time dependence of the gravitational constant $G$.…
The present study deals with dissipative future universe without big rip in context of Eckart formalism. The generalized chaplygin gas, characterized by equation of state $p=-\frac{A}{\rho^\frac{1}{\alpha}}$, has been considered as a model…
We propose and study a scalar extension of the Standard Model which respects a $\mathbb{Z}_3$ symmetry remnant of the spontaneous breaking of a global $U(1)_\text{DM}$ symmetry. Consequently, this model has a natural dark matter candidate…