Statefinder diagnostic for modified Chaplygin gas cosmology in f(R,T) gravity with particle creation

In this paper, we have studied flat Friedmann--Lema\^{\i}tre--Robertson--Walker (FLRW) model with modified Chaplygin gas (MCG) having equation of state p_{m}=A\rho -% \frac{B}{\rho ^{\gamma }}, where $0\leq A\leq 1$, $0\leq \gamma \leq 1$ and $B$ is any positive constant in }${\footnotesize f(R,T)}${\footnotesize \ gravity with particle creation. We have considered a simple parametrization of the Hubble parameter $H$ in order to solve the field equations and discussed the time evolution of different cosmological parameters for some obtained models showing unique behavior of scale factor. We have also discussed the statefinder diagnostic pair $\{r,s\}$ that characterizes the evolution of obtained models and explore their stability. The physical consequences of the models and their kinematic behaviors have also been scrutinized here in some detail.Comment: 21 pages, 23 figures. arXiv admin note: text overlap with arXiv:1603.02573 by other author

Dark energy models from a parametrization of HH: A comprehensive analysis and observational constraints

The presented paper is a comprehensive analysis of two dark energy (DE) cosmological models wherein exact solutions of the Einstein field equations (EFEs) are obtained in a model-independent way (or by cosmological parametrization). A simple parametrization of the Hubble parameter ($H$) is considered for the purpose in the flat Friedmann-Lemaitre-Robertson-Walker (FLRW) background. The parametrization of $H$ covers some known models for some specific values of the model parameters involved. Two models are of special interest which show the behavior of cosmological phase transition from the deceleration in the past to acceleration at late-times. The model parameters are constrained with $57$ points of Hubble datasets together with the $580$ points of Union $2.1$ compilation supernovae datasets and baryonic acoustic oscillation (BAO) datasets. With the constrained values of the model parameters, both the models are analyzed and compared with the standard $\Lambda$CDM model and showing nice fit to the datasets. Two different candidates of DE is considered, cosmological constant $$ and a general scalar field $\phi$ and their dynamics are discussed on the geometrical base built. The geometrical and physical interpretations of the two models in consideration are discussed in details and the evolution of various cosmological parameters are shown graphically. The age of the Universe in both models are also calculated. Various cosmological parametrization schemes used in the past few decades to find exact solutions of the EFEs are also summarized at the end which can serve as a unified reference for the readers.Comment: 28 pages and 22 figure

Anisotropic cosmological models with two fluids

In this paper, aniostropic dark energy cosmological models have been constructed in a Bianchi-V space-time with the energy momentum tensor consisting of two non-interacting fluids namely bulk viscous fluid and dark energy fluid. Two different models are constructed based on the power law cosmology and de Sitter universe. The constructed model also embedded with different pressure gradients along different spatial directions. The variable equation of state (EoS) parameter, skewness parameters for both the models are obtained and analyzed. The physical properties of the models obtained with the use of scale factors of power law and de Sitter law are also presented.Comment: 10 pages, 12 figure

Cosmic acceleration from coupling of baryonic and dark matter components: Analysis and diagnostics

In this paper, we examine a scenario in which late-time cosmic acceleration might arise due to the coupling between baryonic matter and dark matter without the presence of extra degrees of freedom. In this case, one can obtain late-time acceleration in Jordan frame and not in Einstein frame. We consider two different forms of parametrization of the coupling function, and put constraints on the model parameters by using an integrated datasets of Hubble parameter, Type Ia supernova and baryon acoustic oscillations. The models under consideration are consistent with the observations. In addition, we perform the statefinder and $Om$ diagnostics, and show that the models exhibit a distinctive behavior due to the phantom characteristic in future which is a generic feature of the underlying scenario.Comment: 15 pages, 5 figure

LRS Bianchi type-I cosmological model with constant deceleration parameter in f(R,T)f(R,T) gravity

A spatially homogeneous anisotropic LRS Bianchi type-I cosmological model is studied in $f(R,T)$ gravity with a special form of Hubble's parameter, which leads to constant deceleration parameter. The parameters involved in the considered form of Hubble parameter can be tuned to match, our models with the $\Lambda$CDM model. With the present observed value of the deceleration parameter, we have discussed physical and kinematical properties of a specific model. Moreover, we have discussed the cosmological distances for our model.Comment: Published versio

Exact Solution of Field Equation with Constant Ricci Curvature in Finslerian Black Hole

This paper aims to investigate the de Sitter Schwarzschild black hole in the framework of Finslerian space-time because Finslerian geometry can explain problems that Einstein's gravity cannot. For this end, we assume the Ricci curvature is constant in the Finsler space and obtain an exact solution for the field equations in the Finsler space-time. This solution is equivalent to the Finslerian Schwarzschild de Sitter-like black hole. A constant Ricci curvature in Finslerian space-time requires, in its two-dimensional space, the Ricci curvature ($\lambda$) to be constant. We find that for $\lambda\neq1$, this solution resembles a black hole surrounded by a cloud of strings. Furthermore, we investigate null and time-like geodesics for $\lambda=1$.Comment: 20 Pages, 4 figure