相关论文: An Alternative Source for Dark Energy

It is argued that the discovery of cosmic acceleration could have been anticipated on thermodynamic grounds, namely, the generalized second law and the approach to equilibrium at large scale factor. Therefore, the existence of dark energy…

There is compelling evidence that the Universe is undergoing a late phase of accelerated expansion. One of the simplest explanations for this behaviour is the presence of dark energy. A plethora of microphysical models for dark energy have…

As an explanation for the acceleration of the universe, we propose dark matter with self-interactions characterized by a negative pressure; there is no vacuum energy whatsoever in this Cardassian model. These self-interactions may arise due…

It is the common consensus that the expansion of a universe always slows down if the gravity provided by the energy sources therein is attractive and accordingly one needs to invoke dark energy as a source of anti-gravity for understanding…

The fact that the energy densities of dark energy and matter are similar currently, known as the coincidence problem, is one of the main unsolved problems of cosmology. We present here a model in which a spatial curvature of the universe…

In this paper we present a possible origin of dark matter and dark energy from a solution of the Einstein's equation to a primordial universe, which was presented in a previous paper. We also analyze the Dirac's equation in this primordial…

It has recently been proposed that the Universe might be accelerating as a consequence of extra dimensions with time varying size. We show that although these scenarios can lead to acceleration, they run into serious difficulty when taking…

It is shown that dark energy can be obtained from the interplay of the Higgs boson and the inflaton. A key element is the realization that electroweak symmetry breaking can trigger a second phase of rolling of the inflaton, which, when…

The so called `cosmic coincidence' problem seems to suggest a coupling between dark energy and dark matter. A possibility could be given by dark matter particles with masses depending exponentially on the scalar field associated to dark…

Under the assumption that General Relativity (GR) correctly describes the phenomenology of our Universe, astronomical observations provide compelling evidence that (1) the dynamics of cosmic structure is dominated by dark matter (DM), an…

To explain the currently observed accelerated expansion of the universe, a large number of different theoretical models are presently being discussed. In one way or another, all of these contain `new physics', though at different levels.…

I suggest the existence of a still undiscovered interaction: repulsion between matter and antimatter. The simplest and the most elegant candidate for such a force is gravitational repulsion between particles and antiparticles. I argue that…

It is argued that fluctuations of quantum fields in four-dimensional space do not give rise to dark energy, but are rather a negligible contribution to dark matter. By (relativistic) dark matter we mean that the relation between pressure…

There is now strong observational evidence that the expansion of the universe is accelerating. The standard explanation invokes an unknown "dark energy" component. But such scenarios are faced with serious theoretical problems, which has…

We suggest that the eventual gravitational repulsion between matter and antimatter may be a key for understanding of the nature of dark matter and dark energy. If there is gravitational repulsion, virtual particle-antiparticle pairs in the…

I briefly discuss some attempts to construct a consistent modification to General Relativity (GR) that might explain the observed late-time acceleration of the universe and provide an alternative to dark energy. I mention the issues facing…

It is assumed that the quantum vacuum may be studied as consisting of two contributions, with positive and negative energy respectively, which interact but slightly and may be displaced from each other. Then it is proposed that dark matter…

The simplest gauge gravitation theory in Riemann-Cartan space-time leading to the solution of the problem of cosmological singularity and dark energy problem is investigated with purpose to solve the dark matter problem. It is shown that…

Acceleration of the universe might be driven by a continuous elastic medium -- elastic dark energy (Bucher and Spergel 1999). Elastic dark energy can stably support equations of state with pressure to energy ratio w > -4/3. Stable expansion…

The modified F(R)-scalar-Gauss-Bonnet gravity is proposed as dark energy model. The reconstruction program for such theory is developed. It is explicitly demonstrated that the known classical universe expansion history (deceleration epoch,…