Related papers: A tracker solution to the cold dark matter cosmic …
Dark energy, the main constituent in our expanding universe, responsible for its acceleration, is currently being observed with unprecedented precision through various experiments. While several cosmological models can fit this latest data,…
We consider generic models of quintessence and we investigate the influence of massive neutrino matter with field-dependent masses on the matter power spectrum. In case of minimally coupled neutrino matter, we examine the effect in tracker…
Interacting quintessence models have been proposed to explain or, at least, alleviate the coincidence problem of late cosmic acceleration. In this paper we are concerned with two aspects of these kind of models: (i) the dynamical evolution…
We investigate the simplest quintessence dissipative dark matter attractor cosmology characterized by a constant quintessence baryotropic index and a power--law expansion. We show a class of accelerated coincidence--solving attractor…
We investigate non phantom tracker scalar field models as dynamical dark energy scenario. These models can alleviate the cosmic coincidence problem and transition to a cosmological constant-like behaviour at late times. Focusing on the…
The introduction of an interaction for dark energy to the standard cosmology offers a potential solution to the cosmic coincidence problem. We examine the conditions on the dark energy density that must be satisfied for this scenario to be…
It is argued that cosmological models that feature a flow of energy from dark energy to dark matter may solve the coincidence problem of late acceleration (i.e., "why the energy densities of both components are of the same order precisely…
Chameleons are scalar fields whose mass depends on the environment, specifically on the ambient matter density. While nearly massless in the cosmos, where the matter density is tiny, their mass is of order of an inverse millimeter on Earth,…
I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum tensor formally diverges as $k^4$. A cutoff…
Recent cosmological observations strongly suggest that the universe is dominated by an unknown form of energy with negative pressure. Why is this dark energy density of order the critical density today? We propose that the dark energy has…
An oscillating scalar field as a quintessence model for dark energy is proposed. The case of a power-law potential is particularly intriguing and is the focus of the present article. In this model the equation of state w_{OQ} of dark energy…
This study explores the dynamics and phase-space behavior of a multi-component dark energy model, where the dark sector consists of a minimally coupled canonical scalar field and the cosmological constant, using a dynamical system analysis…
Recently, we give the robust $\sim2\,\sigma$ evidences of dynamical dark matter and beyond $2\,\sigma$ signals of the coexistence of dynamical dark matter and dynamical dark energy using current cosmological observations [1]. Here we…
Scalar-tensor theories of gravity provide a consistent framework to accommodate an ultra-light quintessence scalar field. While the equivalence principle is respected by construction, deviations from General Relativity and standard…
We investigate a cosmological model in which dark energy, represented by a quintessential scalar field, is coupled to a dark-matter perfect fluid in the spatially flat Friedmann-Robertson-Walker Universe. This allows an energy exchange in…
In the context of the induced matter theory of gravity, we investigate the possibility of deriving a 4D quintessential scenario where an interaction between dark energy and dark matter is allowed, and the dark energy component is modeled by…
To realize the accelerations in the early and late periods of our universe, we need to specify potentials for the dominant fields. In this paper, by using the Noether symmetry approach, we try to find suitable potentials in the "cosmic…
Dark energy and dark matter are the dominant sources in the evolution of the late universe. They are currently only indirectly detected via their gravitational effects, and there could be a coupling between them without violating…
In some models of thermal relic dark matter, the relic abundance may be set by inelastic scattering processes (rather than annihilations) becoming inefficient as the universe cools down. This effect has been called coscattering. We present…
In cosmology it has become usual to introduce new entities as dark matter and dark energy in order to explain otherwise unexplained observational facts. Here, we propose a different approach treating spacetime as a continuum endowed with…