Viscous Extended Cosmic Chaplygin Gas with Varying Cosmological Constant in FRW Universe

被引:0
作者
G. S. Khadekar
Aina Gupta
S. M. Jogdand
机构
[1] Rashtrasant Tukadoji Maharaj Nagpur University,Department of Mathematics
[2] Shri. Sant Gadge Maharaj College,Department of Mathematics
来源
Iranian Journal of Science and Technology, Transactions A: Science | 2020年 / 44卷
关键词
FRW cosmology; Extended cosmic Chaplygin gas; Bulk viscosity; Cosmological constant;
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摘要
In this paper, we study the viscous extended cosmic Chaplygin gas whose equation of state reduces to extended Chaplygin gas in the limit ω→0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\omega \rightarrow 0$$\end{document} with varying cosmological constant in flat FRW universe. In this framework, we assume the bulk viscosity ζ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\zeta $$\end{document} and cosmological constant Λ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda $$\end{document} as a linear combination of two terms, one is constant and other is a function of dark energy density ρ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rho $$\end{document}. We obtain generalized Friedmann equations due to bulk viscosity, cosmological constant and extended cosmic Chaplygin gas. We calculate the time-dependent dark energy density ρ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rho $$\end{document} for various values of n and α=1/2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha = 1/2$$\end{document} both analytically and numerically. We analyse the behaviour of scale factor, Hubble expansion parameter and deceleration parameter graphically and discuss the stability of the model by using square of speed of sound.
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页码:299 / 309
页数:10
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