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Following the approach of the induced-matter theory, we investigate the cosmological implications of a five-dimensional Brans-Dicke theory, and propose to explain the acceleration of the universe. After inducing in a four-dimensional…
It is obtained that dark energy emerges from higher-derivative gravity with anon-linear terms proportional to $R^2$ and $R^3$ with $R$ being the Ricci scalar curvature. Interestingly, it is found that the universe begins with acceleration,…
The origin of the observed acceleration of the expansion of the universe is a major problem of modern cosmology and theoretical physics. Simple estimations of the contribution of vacuum to the density energy of the universe in quantum field…
We investigate the clustering properties of a dynamical dark energy component. In a cosmic mix of a pressureless fluid and a light scalar field, we follow the linear evolution of spherical matter perturbations. We find that the scalar field…
A huge amount of good quality astrophysical data converges towards the picture of a spatially flat universe undergoing the today observed phase of accelerated expansion. This new observational trend is commonly addressed as Precision…
Plane symmetric cosmological models are investigated with or without any dark energy components in the field equations. Keeping an eye on the recent observational constraints concerning the accelerating phase of expansion of the universe,…
The paper deals with a spatially homogeneous and anisotropic universe filled with perfect fluid and dark energy components. The two sources are assumed to interact minimally together with a special law of variation for the average Hubble's…
Main aim of this work is to give a suitable explanation of present accelerating universe through an acceptable interactive dynamical cosmological model. A three-fluid cosmological model is introduced in the background of…
A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is…
The discovery ten years ago that the expansion of the Universe is accelerating put in place the present cosmological model, in which the Universe is composed of 4% baryons, 20% dark matter, and 76% dark energy. Yet the underlying cause of…
A large number of recent observational data strongly suggest that we live in a flat, accelerating Universe composed of $\sim$ 1/3 of matter (baryonic + dark) and $\sim$ 2/3 of an exotic component with large negative pressure, usually named…
This article discusses a dark energy cosmological model in the standard theory of gravity - general relativity with a broad scalar field as a source. Exact solutions of Einstein's field equations are derived by considering a particular form…
A new cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation…
The problem of cosmic acceleration and dark energy is one of the mysteries presently posed in the scientific society that general relativity has not been able to solve. In this work, we have considered alternative models to explain this…
The acceleration of the cosmic expansion is a fundamental challenge to standard models of particle physics and cosmology. The new physics of dark energy may lie in the nature of gravity, the quantum vacuum, or extra dimensions. I give a…
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…
The recent discovery of apparent cosmic acceleration has highlighted the depth of our ignorance of the fundamental properties of nature. It is commonly assumed that the explanation for acceleration must come from a new form of energy…
Attractor solutions that give dynamical reasons for dark energy to act like the cosmological constant, or behavior close to it, are interesting possibilities to explain cosmic acceleration. Coupling the scalar field to matter or to gravity…
In this paper, we investigate a scenario in which late time cosmic acceleration might arise due to coupling between dark matter and baryonic matter without resorting to dark energy or large scale modification of gravity associated with…
A nonminimally coupled hybrid dark energy model is introduced. The dark energy evolution is triggered by mass varying neutrinos. Quintessence evolution begins from an initial point, with an insignificant dark energy density, and arrives at…