相关论文: Gravity assisted dark energy dominance and cosmic …
A successor to the standard hot big-bang cosmology is emerging. It greatly extends the highly successful hot big-bang model. A key element of the New Standard Cosmology is dark energy, the causative agent for accelerated expansion. Dark…
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…
A ghost-free theory of gravity with two dynamical metrics both coupled to matter is shown to be consistent and viable. Its cosmological implications are studied, and the models, in particular in the context of partially massless gravity,…
We review some of the well-known features of quantum cosmology, such as the factor ordering problem, the wave function and the density matrix, for a dark energy dominated universe, where analytical solutions can be obtained. For the…
The discovery of cosmic acceleration has stimulated theorists to consider dark energy or modifications to Einstein's General Relativity as possible explanations. The last decade has seen advances in theories that go beyond smooth dark…
In this paper we introduce the fractional dark energy model, in which the accelerated expansion of the Universe is driven by a nonrelativistic gas (composed by either fermions or bosons) with a noncanonical kinetic term. The kinetic energy…
In this work, we reconstruct the $f(R)$ modified gravity for different ghost and generalized ghost dark energy models in FRW flat universe, which describe the accelerated expansion of the universe. The equation of state of reconstructed…
The principles of General Relativity allow for a non-vanishing cosmological constant, which can possibly be interpreted at least partially in terms of quantum-fluctuations of matter fields. Depending on sign and magnitude it can cause…
In the present work, an alternative interpretation of the source of accelerated expansion of the Universe is suggested. A probable candidate is the interaction between the quantum spin of a moving particle and the torsion of space-time,…
The existence of current-time universe's acceleration is usually modeled by means of two main strategies. The first makes use of a dark energy barotropic fluid entering \emph{by hand} the energy-momentum tensor of Einstein's theory. The…
Within the standard cosmological scenario the Universe is found to be filled by obscure components (dark matter and dark energy) for ~95% of its energy budget. In particular, almost all the matter content in the Universe is given by dark…
Our standard model of the Universe predicts the distribution of dark matter to $1\%$ at the scales needed for upcoming experiments, yet our predictions for how the luminous matter -- which has interactions besides gravity -- is distributed…
In this work we review some of the theoretical efforts and experimental evidences related to Dark matter and Dark energy problems in the universe. These dilemmas show us how incomplete our knowledge of gravity is, and how our concepts about…
We construct a multimetric gravity theory containing N >= 3 copies of standard model matter and a corresponding number of metrics. In the Newtonian limit, this theory generates attractive gravitational forces within each matter sector, and…
A formalism for the appearance of dark energy in the matter dominated era, leading to a persistent de Sitter expansion at the late time is proposed. Our framework is a hybrid quintessence model with a non-minimal coupling to the Ricci…
A generic feature of viable exponential $F(R)$-gravity is investigated. An additional modification to stabilize the effective dark energy oscillations during matter era is proposed and applied to two viable models. An analysis on the future…
The issues of quintessence and cosmic acceleration can be discussed in the framework of higher order theories of gravity. We can define effective pressure and energy density directly connected to the Ricci scalar of curvature of a generic…
A bimetric description of the universe is proposed, which explains cosmic acceleration deduced from optically observed high-redshift objects. This phenomenon is classically charged to a mysterious repulsive "dark energy" whose true nature…
We review the state of the art of f(R) theories of gravity (in their various formulations), which have been proposed as an explanation of the cosmic acceleration alternative to dark energy. The successes of f(R) gravity are discussed,…
We suggest the possibility that the mysterious dark energy component driving the acceleration of the Universe is the leading term, in the de Sitter temperature, of the free energy density of space-time seen as a quantum gravity coherent…