关于全息暗能量及其在Brans-Dicke宇宙中相关问题的理论研究

发布时间：2018-03-17 04:12

本文选题：暗能量　切入点：修正的Chaplygin气体　出处：《辽宁师范大学》2011年硕士论文　论文类型：学位论文

【摘要】：近些年来出现了大量的而且越来越精确的天文观测数据,这对于宇宙学的研究给予了巨大的支持。按照Ia型超新星的观测数据,我们了解到当今宇宙处于加速膨胀阶段,当然微波背景辐射能谱的观测和大尺度结构也能够证明这一观点。之后围绕着怎样从理论上解释宇宙当今加速膨胀现象,人们提出的方法分为两大类。第一类是修正爱因斯坦-希尔伯特作用量,即引力修正理论。第二类是认为在宇宙中均匀分布着一种新的、具有负压强的成分,即暗能量。本文首先介绍了宇宙学的理论基础,包括标准宇宙学模型、暴胀理论,之后为了解释当今宇宙的加速膨胀,介绍了几种常见的暗能量模型。本文主要从两个方面入手,对当今宇宙的加速膨胀问题进行理论研究。首先,将全息暗能量作为修正的Chaplygin气体(MCG)模型的暗能量成分,并且考虑宇宙中含有重子物质,而且暗物质和全息暗能量之间有相互作用。在模型分析中,通过推导给出了宇宙学量(密度参数、态参数、减速参数)的演化曲线,图像告诉该模型的演化是从减速到加速膨胀的,可以解释加速膨胀,态参数可以穿越-1,并且各宇宙学量的今天值也和当今观测数据吻合的比较好,之后对模型进行了几何诊断,具体包括s-r图、q-r图和ω-ω'图,通过图像我们不仅看到全息常数c和相互作用常数b对模型的演化起着非常重要的影响,而且也看到该模型和LCDM模型的差别。而且,本文也对模型做了Om诊断,通过图像展示出HDE模型和LCDM模型的区别。然后,通过在Brans-Dicke宇宙学中,推广前人的工作到新的全息暗能量(NHDE)模型中。具体的,在非平直的Brans-Dicke宇宙中建立了NHDE模型和Quintessence, Tachyon, K-essence, Dilaton, CG模型的对应。不仅如此,本文还有重建了这些模型的场和势,发现新全息Quintessence和新全息CG的场和势在平直空间中、在一定的条件下则是相同的,但是在非平直宇宙中是完全不同的。对于新全息Quintessence和新全息CG模型,如果势中参数满足一定的条件,在Brans-Dicke理论下能够解释宇宙加速膨胀。另外值得注意的是,本文不仅在Brans-Dicke理论框架下给出了一些NHDE模型的新结果,而且在参数满足一定条件时,Brans-Dicke理论退化为广义相对论,可以得到一些前人得到的结果,这些结果在一定条件下也能够描述宇宙的加速膨胀。
[Abstract]:In recent years, there have been large and increasingly accurate astronomical observations, which have given great support to the study of cosmology. According to the observational data of Type Ia supernova, we know that the universe is now in an accelerated expansion stage. Of course, observations of microwave background radiation spectra and large scale structures can also prove this view, and then revolve around how to theoretically explain the accelerating expansion of the universe today. The proposed methods can be divided into two categories: the first is the modification of Einstein Hilbert action, that is, the gravitational correction theory, and the second is that there is a new kind of uniform distribution in the universe, that is, dark energy, which has a strong negative pressure. This paper first introduces the theoretical basis of cosmology, including the standard cosmological model, inflation theory, and then, in order to explain the accelerating expansion of the universe today, several common dark energy models are introduced. A theoretical study of the accelerating expansion of the universe is carried out. Firstly, the holographic dark energy is considered as the dark energy component of the modified Chaplygin gas model, and the interaction between dark matter and holographic dark energy is considered in the model analysis. The evolution curve of cosmological quantities (density parameter, state parameter, deceleration parameter) is derived. The image shows that the evolution of the model is from deceleration to acceleration expansion, which can explain the accelerated expansion. The state parameters can traverse -1, and the present values of the cosmological quantities are in good agreement with today's observational data. Then the geometric diagnosis of the model is carried out, including the s-r map q-r diagram and 蠅-蠅 'graph. From the image we not only see that the holographic constant c and the interaction constant b play a very important role in the evolution of the model, but also see the difference between the model and the LCDM model. The difference between HDE model and LCDM model is shown by image. Then, by popularizing the previous work in Brans-Dicke cosmology to the new holographic dark energy model, the author establishes the correspondence between the NHDE model and the Quintessence, Tachyon, K-essence, Dilaton, CG models in the non-straight Brans-Dicke universe. In this paper, we also reconstruct the fields and potentials of these models and find that the fields and potentials of the new holographic Quintessence and the new holographic CG are the same in the flat space and under certain conditions. For the new holographic Quintessence model and the new holographic CG model, if the parameters in the potential satisfy certain conditions, the accelerating expansion of the universe can be explained under the Brans-Dicke theory. In this paper, we not only give some new results of the NHDE model under the framework of Brans-Dicke theory, but also degenerate the Brans-Dicke theory into general relativity when the parameters satisfy certain conditions. These results can also describe the accelerating expansion of the universe under certain conditions.
【学位授予单位】：辽宁师范大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：P145.9

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