Deceleration parameter

About: Deceleration parameter is a research topic. Over the lifetime, 1776 publications have been published within this topic receiving 89440 citations.

Reconstruction of $f(R)$, $f(T)$ and $f(\mathcal{G})$ models inspired by variable deceleration parameter

Abstract: We study an special law for the deceleration parameter, recently proposed by Akarsu and Dereli, in the context of $f(R)$, $f(T)$ and $f(\mathcal{G})$ theories of modified gravity. This law covers the law of Berman for obtaining exact cosmological models to account for the current acceleration of the universe, and also gives the opportunity to generalize many of the dark energy models having better consistency with the cosmological observations. Our aim is to reconstruct the $f(R)$, $f(T)$ and $f(\mathcal{G})$ models inspired by this law of variable deceleration parameter. Such models may then exhibit better consistency with the cosmological observations.

Bianchi type-I models in self-creation cosmology with constant deceleration parameter

Abstract: We have studied the evolution of homogeneous and anisotropic Bianchi type-I cosmological models filled with perfect fluid in Barber second self-creation theory by assuming a special law of variation for Hubble’s parameter that yield a constant value of deceleration parameter. Some physical consequences of the models have been discussed in case of Zel’dovich fluid and radiation dominated fluid.

Power Law and Logarithmic Entropy Corrected Ricci Dark Energy Models in Brans-Dicke Chameleon Cosmology

Abstract: In this work, we study the power-law and the logarithmic entropy corrected versions of the Ricci Dark Energy (RDE) model in the framework of the Brans-Dicke cosmology non-minimally coupled with a chameleon scalar field ϕ. Considering the presence of interaction between Dark Energy (DE) and Dark Matter (DM), we derived the expressions of some relevant cosmological parameters, i.e. the equation of state parameter ω D , the deceleration parameter q and the evolution of the energy density parameter $\varOmega'_{D}$ .

The dynamical evolution of 3-space in a higher dimensional steady state universe

Abstract: We investigate a class of cosmological solutions of Einstein’s field equations in higher dimensions with a cosmological constant and an ideal fluid matter distribution as a source We discuss the dynamical evolution of the universe subject to two constraints that (i) the total volume scale factor of the universe is constant and (ii) the effective energy density is constant We obtain various interesting new dynamics for the external space that yield a time varying deceleration parameter including oscillating cases when the flat/curved external and curved/flat internal spaces are considered We also comment on how the universe would be conceived by an observer in four dimensions who is unaware of the extra dimensions