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Unified dark fluid and cosmic transit models in Brans–Dicke theory
Physics of the Dark Universe ( IF 5.0 ) Pub Date : 2020-09-24 , DOI: 10.1016/j.dark.2020.100722
Sunil K. Tripathy , Sasmita Kumari Pradhan , Zashmir Naik , Dipanjali Behera , B. Mishra

Some dark energy cosmological models are constructed in the framework of a generalised Brans–Dicke theory which contains a self interacting potential and a dynamical coupling parameter. The models are constructed in the background of an anisotropic metric. The dark sector of the universe is considered through a unified linear equation of state. The parameters of the unified dark fluid have been constrained from some physical basis. Since the universe is believed to have undergone a transition from an early deceleration to a late time acceleration, the deceleration parameter should have a signature flipping behaviour at the transition redshift. We have used a hybrid scale factor to simulate the dynamical behaviour of the deceleration parameter. Basing upon the observational constraints on the transition redshift, we have constructed four different transitioning dark energy models. The constructed models are confronted with observational data. For all the models, the behaviour of the dynamical scalar field, Brans–Dicke parameter are investigated. Also, on the basis of the generalised Brans–Dicke theory, we have estimated the time variation of the Newtonian gravitational constant.



中文翻译:

布朗斯-迪克理论中统一的暗流体和宇宙传输模型

在广义的布朗斯-迪克理论的框架内构造了一些暗能量宇宙学模型,该模型包含一个自相互作用的势能和一个动力学耦合参数。这些模型是在各向异性度量的背景下构建的。通过统一的线性状态方程来考虑宇宙的暗区。统一的深色液体的参数已从某种物理基础上受到限制。由于认为宇宙已经历了从早期减速到晚期加速的过渡,因此减速参数在过渡红移时应具有特征翻转行为。我们使用了混合比例因子来模拟减速参数的动力学行为。基于对转换红移的观测约束,我们构建了四个不同的过渡暗能量模型。所构建的模型面临着观测数据。对于所有模型,都研究了动态标量场的行为,Brans–Dicke参数。另外,根据广义的Brans–Dicke理论,我们估计了牛顿重力常数的时间变化。

更新日期:2020-09-29
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