Related papers: Future evolution in a backreaction model and the a…
In this contribution we summarize two recent applications of a correspondence between backreaction terms in averaged inhomogeneous cosmologies and an effective scalar field (the `morphon'). Backreaction terms that add to the standard…
We investigate the late time acceleration of the universe in the context of the Stephani model. This solution generalizes those of Friedmann-Lemaitre-Robertson-Walker (FLRW) in such a way that the spatial curvature is a function of of time.…
Numerical modeling of a mathematical model of the cosmological evolution of an asymmetric scalar doublet with kinetic interaction between the components was carried out. A wide range of values of fundamental parameters and initial…
While considering the chameleon scalar field model with the spatially flat FLRW background, we investigate the late-time acceleration phase of the universe, wherein we apply the typical potential usually used in this model. Through setting…
Spatially averaged inhomogeneous cosmologies in classical general relativity can be written in the form of effective Friedmann equations with sources that include backreaction terms. In this paper we propose to describe these backreaction…
The exact solution of a two-scale Buchert average of the Einstein equations is derived for an inhomogeneous universe which represents a close approximation to the observed universe. The two scales represent voids, and the bubble walls…
The effective evolution of an inhomogeneous universe model in any theory of gravitation may be described in terms of spatially averaged variables. In Einstein's theory, restricting attention to scalar variables, this evolution can be…
A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the coincidence and magnitude fine-tuning problems of the Cosmological Constant…
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…
We use cosmological perturbation theory to study the backreaction effects of a self-consistent and well-defined cosmological averaging on the dynamics and the evolution of the Universe. Working with a perturbed…
In the present work, the flat FLRW Universe has been modelled with cosmic matter in the form of diffusive barotropic fluid. The diffusive fluid undergoes dissipation due to diffusion mechanism in the form of cosmological scalar field. From…
Quantum fluctuations of a nonminimally coupled scalar field in D-dimensional homogeneous and isotropic background are calculated within the operator formalism in curved models with time evolutions of the scale factor that allow smooth…
The behaviour of the flat anisotropic model of the Universe with a scalar field is explored within the framework of quantum cosmology. The principal moment of the account of an anisotropy is the presence either negative potential barrier or…
We considered the phantom cosmology with a lagrangian $\displaystyle L=\frac{1}{\eta}[1-\sqrt{1+\eta g^{\mu\nu}\phi_{, \mu}\phi_{, \nu}}]-u(\phi)$, which is original from the nonlinear Born-Infeld type scalar field with the lagrangian…
Recent observations of Type Ia supernovae provide evidence for the acceleration of our universe, which leads to the possibility that the universe is entering an inflationary epoch. We simulate it under a ``big bounce'' model, which contains…
We present a realistic scenario of tracking of scalar fields with varying equation of state. The astrophysical constraints on the evolution of scalar fields in the physical universe are discussed. The nucleosynthesis and the galaxy…
Unimodular quantum cosmology admits wavepacket solutions that evolve according to a kind of Schr\"odinger equation. Though this theory is equivalent to general relativity on the classical level, its canonical structure is different and the…
A model for the universe with both acceleration and deceleration is given. The model incorporates an initial acceleration, then a deceleration as has been observed by Schaefer in respect of gamma ray bursts, a second phase of acceleration…
We revisit the causal backreaction paradigm, in which the need for Dark Energy is eliminated via the generation of an apparent cosmic acceleration from the causal flow of inhomogeneity information coming in towards each observer from…
There is an ongoing debate in the literature as to whether the effects of averaging out inhomogeneities (``backreaction'') in Cosmology can be large enough to account for the acceleration of the scale factor in the FLRW models. In…