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arXiv 1606.00702gr-qc
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Brans-Dicke引力框架下膨胀宇宙物质含量的时间演化

Time Evolution of the Matter Content of the Expanding Universe in the Framework of Brans-Dicke Gravity

Sudipto Roy

摘要:

在Brans-Dicke(BD)引力框架下,基于物质与暗能量的相互转换,建立了无压尘埃时代空间平坦的宇宙模型.为了说明物质含量的非守恒性,在物质密度的表达式中任意加入了一个时间函数f(t)。根据定义,f(t)与宇宙的物质含量成正比。通过对标度因子和标量场的适当处理,由BD场方程确定了f(t)的函数形式。比例因子的选择应使减速参数随时间发生特征翻转。函数f(t)随时间单调递减,表明物质转化为暗能量。确定了宇宙中物质和暗能量的比例随时间的变化关系。本文探讨了物质含量不守恒对各种宇宙学参数的影响。提出了两种物质-能量相互作用模型,并将f(t)表示为相互作用项的函数。暗能量状态方程(EoS)参数用f(t)表示并进行了分析。

英文摘要:

A cosmological model has been constructed in the framework of Brans-Dicke (BD) gravity, based on an inter-conversion between matter and dark energy, for a spatially flat universe in the era of pressureless dust. To account for the non-conservartion of the matter content, a function of time f(t) has been arbitrarily put into the expression of the density of matter. By definition, f(t) is proportional to the matter content of the universe. Using suitable ansazes for scale factor and scalar field, the functional form of f(t) has been determined from the BD field equations. The scale factor has been so chosen that it would cause a signature flip of the deceleration parameter with time. The function f(t) decreases monotonically with time, indicating a transformation of matter into dark energy. Time dependence of the proportions of matter and dark energy of the universe has been determined. The effect of non-conservation of the matter content upon various cosmological parameters has been explored in the present study. Two models of matter-energy interaction have been proposed and f(t) has been expressed as a function of their interaction term. The dark energy equation-of-state (EoS) parameter has been expressed and analyzed in terms of f(t).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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