Related papers: Virialization-induced curvature versus dark energy
A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the magnitude and coincidence fine-tuning problems of the Cosmological Constant…
In this letter, we consider the possibility of reconciling metric theories of gravitation with violation of the conservation of energy-momentum. Under some circumstances, this can be achieved in the context of unimodular gravity, and it…
Following the idea of the induced matter theory, for a non-vacuum five-dimensional version of general relativity, we propose a model in which the induced terms emerging from the extra dimension in our four-dimensional space-time, supposed…
The concordance model of cosmology suffers from the major theoretical problems surrounding the observed value and recent emergence of a cosmological constant. In this paper we present a novel approach, which explains more naturally its…
Since its decovery during the late 90's, the dimming of distant SN Ia apparent luminosity has been mostly ascribed to the influence of a mysterious dark energy component. Based upon the cosmological "principle" hypothesis, this…
Discrepancies between distance measurements and $\Lambda$CDM predictions reveal notable features in the distance-redshift relation, possibly suggesting the presence of an evolving dark energy component. Given the central role of the…
By relaxing the conventional assumption of a purely gravitational interaction between dark energy and dark matter, substantial alterations to the growth of cosmological structure can occur. In this work we focus on the homogeneous transfer…
Distance-redshift data can impose strong constraints on dark energy models even when the equation of state is oscillatory. Despite the double integral dependence of the distance on the equation of state, precision measurement of the…
We present a brief review of various approaches to late time acceleration of universe. The cosmological relevance of scaling solutions is emphasized in case of scalar field models of dark energy. The underlying features of a variety of…
We have investigated the evolution of a homogeneous isotropic background of the Universe and inhomogeneous subhorizon matter density perturbations in viable $f(R)$ models of present dark energy and cosmic acceleration analytically and…
To explain the cosmic speed up, brought to light by the recent SNIa and CMB observations, we propose the following: a) In a spacetime endowed with a FRW metric, we choose an empirical scale factor that best explains the observations. b) We…
We use the spherical collapse model to demonstrate that the observable average density of virialized clusters depends on the properties of dark energy along with the properties of gravity on cluster scales and can therefore be used as a…
Observational cosmology provides us with a large number of high precision data which are used to derive models trying to reproduce ``on the mean'' our observable patch of the Universe. Most of these attempts are achieved in the framework of…
Cosmic acceleration is explained quantitatively, purely in general relativity, as an apparent effect due to quasilocal gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe.…
In this paper we analyse the possibility of having homogeneous isotropic cosmological models with observers reaching $t=\infty$ in finite proper time. It is shown that just observationally-suggested dark energy models with $w\in(-5/3,-1)$…
A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by cosmic structure formation, without resort to Dark Energy, modifications to gravity, or a local void. The observed acceleration…
The Starobinsky model of modified gravity suggested to explain dark energy may be also considered in the astrophysical context. Recently it has been pointed out that in contracting regions curvature oscillations around the GR value may lead…
We study the cosmology with the running dark energy. The parametrization of dark energy with the respect to the redshift is derived from the first principles of quantum mechanics. Energy density of dark energy is obtained from the quantum…
The homogeneous expansion history H(z) of our universe measures only kinematic variables, but cannot fix the underlying dynamics driving the recent acceleration: cosmographic measurements of the homogeneous universe, are consistent with…
Motivated by the cosmological constant and the coincidence problems, we consider a cosmological model where the dark sectors are interacting together through a phenomenological decay law $\dot{\rho}_{\Lambda}=Q\rho_{\Lambda}^n$ in a FRW…