关于加速膨胀宇宙中f（R）引力模型构建的研究

发布时间：2018-02-02 16:05

本文关键词： 加速膨胀暗能量 f(R)引力理论态参数　出处：《辽宁师范大学》2013年硕士论文　论文类型：学位论文

【摘要】：索尔佩尔马特、布莱恩.施密特以及亚当.里斯三位天体物理学家对超新星进行研究,并因此获得2011年诺贝尔物理学奖。超新星的观测事实表明,宇宙在加速膨胀。为了能解释这一现象,物理学家们提出了一系列的理论,诸如暗能量理论和修正引力等。其中宇宙学常数、标量场、修正的Chapplygin气体(MCG)等模型是常见的暗能量模型。修正引力理论也可以解释观测结果,其中的f(R)理论极具代表性已经被广泛研究。既然暗能量理论可以引起宇宙的加速,且其态参数具有一定的取值范围,同样地,写成具有曲率形式能量密度的f(R)引力理论也可以引起加速,那么我们就可以从已知的宇宙加速膨胀这一事实出发,选用具有f(R)曲率形式能量密度和相应的暗能量能量密度相等构建出对应的f(R)的具体表达形式。根据适当的初始条件计算出态参数,并对相关参数进行限定,得到的结果和原来已经构建的f(R)的表达形式相比较。本文将取全息里奇暗能量、代表标量场的Quintessence模型、MCG模型在物质与曲率没有耦合和任意耦合下来构建相应的f(R)表达形式和具体的态参数,并且与观测值相比较,对相应的参数进行限制和检验。结果发现它们都可以构建出具有曲率R的正负幂次关系的f(R),这些结果与之前直接提出的修正引力中的f(R)的正负幂次相似,而MCG构建的结果还可以有更为复杂的形式。另外还发现,对相应的参数进行限制,计算出的态参数可以很好地满足宇宙加速下的态参数值。
[Abstract]:Three astrophysicists, Saul Permat, Brian Schmidt and Adam Reese, studied supernovae and won the Nobel Prize in Physics in 2011. In order to explain this phenomenon, physicists have put forward a series of theories, such as dark energy theory and modified gravity. The modified Chapplygin gas model is a common dark energy model. The modified gravity theory can also explain the observed results. The theory of fen R) has been widely studied. Since the dark energy theory can cause the acceleration of the universe and its state parameters have a certain range of values, the gravity theory written as the energy density of curvature form can also cause acceleration. So we can start with the fact that the universe is accelerating. The energy density with the curvature form and the corresponding dark energy energy density are chosen to construct the specific expression form of the corresponding FG R) and the state parameters are calculated according to the appropriate initial conditions. The relative parameters are defined and the results are compared with the expression of the previously constructed fen Rs. In this paper, the holographic Ritchie dark energy is used to represent the Quintessence model of scalar field. The expression form and specific state parameters of MCG model are constructed without coupling of matter and curvature and arbitrary coupling, and are compared with observed values. The results show that the positive and negative power relations with curvature R can be constructed by using these parameters. These results are similar to the positive and negative power of modified gravity, and the results of MCG construction can have more complicated form. In addition, it is found that the corresponding parameters are restricted. The calculated state parameters can well meet the values of state parameters under cosmic acceleration.
【学位授予单位】：辽宁师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P159

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