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相关论文: About Bianchi I with VSL

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We have examined the cosmological actions of LRS (Locally Rationally Symmetric) Bianchi type-I universe model in $f(R,T^\psi)$ gravity. For this, we have estimated the Hubble parameter, the effective equation of state parameter…

广义相对论与量子宇宙学 · 物理学 2026-01-07 Mohit Thakre , Praveen Kumar Dhankar , Safiqul Islam , Parbati Sahoo , Farook Rahaman , Behnam Pourhassan

In a recent paper \cite{1}, we have studied the vacuum solutions of Bianchi types I and V spacetimes in the framework of metric f(R) gravity. Here we extend this work to perfect fluid solutions. For this purpose, we take stiff matter to…

广义相对论与量子宇宙学 · 物理学 2010-10-28 M. Sharif , M. Farasat Shamir

In this paper, the crucial phenomenon of the expansion of the universe has been discussed. For this purpose, we study the vacuum solutions of Bianchi types $I$ and $V$ spacetimes in the framework of $f(R)$ gravity. In particular, we find…

广义相对论与量子宇宙学 · 物理学 2010-05-07 M. Sharif , M. Farasat Shamir

Bianchi I cosmological models consisting of a fluid with both bulk and shear viscosity are studied. It is shown how the dynamical importance of the shear and the fluid density change in the course of evolution. Exact solutions with an…

广义相对论与量子宇宙学 · 物理学 2021-03-15 A. Banerjee , S. B. Duttachoudhury , Abhik Kumar Sanyal

This paper is devoted to investigate the exact solutions of Bianchi types I and V spacetimes in the context of f(R, T) gravity [1]. For this purpose, we found two exact solutions in each case by using assumption of constant deceleration…

广义相对论与量子宇宙学 · 物理学 2012-07-04 M. Farasat Shamir , Adil Jhangeer , Akhlaq Ahmad Bhatti

We investigate a new class of LRS Bianchi type-II cosmological models by revisiting in the paper of Mishra {\it et al} (2013) by considering a new deceleration parameter (DP) depending on the time in string cosmology for the modified…

综合物理 · 物理学 2021-08-02 Archana Dixit , Rashid Zia , Anirudh Pradhan

We study the global dynamical behavior of spatially homogeneous solutions of the Einstein equations in Bianchi type I symmetry, where we use non-tilted elastic matter as an anisotropic matter model that naturally generalizes perfect fluids.…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Simone Calogero , J. Mark Heinzle

We use a dynamical systems approach to study Bianchi type VI$_0$ cosmological models containing two tilted $\gamma$-law perfect fluids. The full state space is 11-dimensional, but the existence of a monotonic function simplifies the…

广义相对论与量子宇宙学 · 物理学 2009-11-10 Alan A. Coley , Sigbjorn Hervik

In this paper we have investigated an LRS Bianchi I anisotropic cosmological model of the universe by taking time varying $G$ and $\Lambda$ in the presence of bulk viscous fluid source described by full causal non-equilibrium…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Anirudh Pradhan , Purnima Pandey , G. P. Singh , R. V. Deshpandey

We have studied the locally rotationally symmetric (LRS) Bianchi type-I cosmological model in $f(R,T)$ gravity ($R$ is the Ricci scalar and $T$ is the trace of the stress energy tensor) with Bulk viscous fluid as matter content. The model…

广义相对论与量子宇宙学 · 物理学 2018-03-29 Parbati Sahoo , Raghavender Reddy

The dynamics of a class of cosmological models with collisionless matter and four Killing vectors is studied in detail and compared with that of corresponding perfect fluid models. In many cases it is possible to identify asymptotic states…

广义相对论与量子宇宙学 · 物理学 2009-10-31 A. D. Rendall , K. P. Tod

An LRS Bianchi type-V cosmological models representing a viscous fluid distribution with a time dependent cosmological term $\Lambda$ is investigated. To get a determinate solution, the viscosity coefficient of bulk viscous fluid is assumed…

广义相对论与量子宇宙学 · 物理学 2007-08-06 Anirudh Pradhan , J. P. Shahi , C. V. Singh

In this paper the dynamics of free gauge fields in Bianchi type I-VII$_{h}$ space-times is investigated. The general equations for a matter sector consisting of a $p$-form field strength ($p\,\in\,\{1,3\}$), a cosmological constant…

广义相对论与量子宇宙学 · 物理学 2018-04-10 Ben David Normann , Sigbjørn Hervik , Angelo Ricciardone , Mikjel Thorsrud

By employing the Bianchi identities for the Riemann tensor in conjunction with the Einstein equations, we construct a first order symmetric hyperbolic system for the evolution part of the Cauchy problem of general relativity. In this…

广义相对论与量子宇宙学 · 物理学 2012-08-27 Arlen Anderson , Yvonne Choquet-Bruhat , James W. York,

In this work, we study the effect of a magnetic field on the growth of cosmological perturbations. We develop a mathematical consistent treatment in which a perfect fluid and a uniform magnetic field evolve together in a Bianchi I universe.…

广义相对论与量子宇宙学 · 物理学 2019-11-19 Federico Di Gioia , Giovanni Montani

The locally rotationally symmetric tilted perfect fluid Bianchi type V cosmological model provides examples of future geodesically complete spacetimes that admit a `kinematic singularity' at which the fluid congruence is inextendible but…

广义相对论与量子宇宙学 · 物理学 2009-10-06 A. A. Coley , S. Hervik , W. C. Lim , M. A. H. MacCallum

This paper is devoted to study Bianchi type I cosmological model in Brans-Dicke theory with self-interacting potential by using perfect, anisotropic and magnetized anisotropic fluids. We assume that the expansion scalar is proportional to…

广义相对论与量子宇宙学 · 物理学 2015-06-04 M. Sharif , Saira Waheed

In this paper we investigate a potential use of fluid approximation techniques in the context of stochastic model checking of CSL formulae. We focus on properties describing the behaviour of a single agent in a (large) population of agents,…

计算机科学中的逻辑 · 计算机科学 2013-01-22 Luca Bortolussi , Jane Hillston

In this paper, we investigate Bianchi type$-V$ cosmological models with bulk viscous fluid and time varying cosmological $\Lambda$ and Newtonian $G$ parameters. The Einstein's field equations have been transformed into a coupling…

A new class of a spatially homogeneous and anisotropic Bianchi type-I cosmological models of the universe for perfect fluid distribution within the framework of scalar-tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett.…

综合物理 · 物理学 2012-11-15 Anirudh Pradhan , Ajay Kumar Singh , H. Amirhashchi