含粘性的统一暗流体模型与球状塌缩

发布时间：2017-12-31 04:14

本文关键词：含粘性的统一暗流体模型与球状塌缩　出处：《大连理工大学》2016年博士论文　论文类型：学位论文

【摘要】：近些年来,大量的天文观测数据(如Ia型超新星,宇宙微波背景辐射以及物质功率谱等等)强烈表明目前宇宙正经历着加速膨胀的过程,并且这种加速膨胀是由一种约占据宇宙总能量96%的未知暗流体所驱动。这种暗流体通常被分解为两部分：暗物质和暗能量。然而目前的引力探测水平并不能把这两种成分有效地区分开来(这被称为暗简并问题),并且到目前为止没有可靠的物理原理支持任何形式的分解。这激励研究者们提出一些统一暗物质和暗能量的理论模型来研究宇宙。这些统一的宇宙模型的共同特点是将充满宇宙空间的介质视作理想流体来对待,并且所研究的扰动都是绝热的。随着宇宙学观测限制与理论模型之间出现矛盾,一些学者又提出应该考虑宇宙介质的非绝热扰动。也就是说宇宙中的介质有可能并非理想流体,而是含有粘性的非理想流体。这种含粘性的模型因为使非绝热扰动成为其内禀的属性而备受青睐。本论文主要研究具有体积粘性的统一暗流体模型的宇宙学观测限制工作以及体积粘性在宇宙大尺度结构形成过程中所产生的影响。首先概述宇宙学的发展历史、研究内容及背景知识。然后介绍目前主要的天文观测和几种常见的宇宙学理论模型。本论文的主要研究工作在第三章、第四章及附录部分。在第三章,研究一种具有体积粘性的统一GCG模型,我们首次考虑体积粘性的扰动情况。利用天文观测数据对模型的参数空间进行限制,得到新增模型参数—体积粘性系数ζ0在3σ范围内的取值,并且还讨论了体积粘性对态方程参数和有效绝热声速的演化过程的影响。第四章,我们探讨VGCG模型的球状塌缩过程,分析讨论体积粘性对宇宙大尺度结构形成(即塌缩过程)的影响,并且将结果与ACDM模型的结果进行比较。本文最后一章是总结和展望。此外,附录部分介绍了宇宙学的扰动理论(包含体积粘性的扰动),并且给出了密度扰动和速度扰动方程的具体导出过程。
[Abstract]:In recent years, a large number of astronomical data (such as a type I supernova, the cosmic microwave background radiation and matter power spectra etc.) strongly suggest that the universe is undergoing the process of accelerated expansion, and the accelerated expansion is driven by a accounted for 96% of the total energy cosmic unknown dark fluid. This dark fluid is usually decomposed two part: dark matter and dark energy. However, the gravity probe level cannot separate the two components of effective area (this is called dark degeneracy problem), and so far no physical principle and reliable support for decomposition of any form. This incentive researchers put forward some uniform and dark matter the dark energy theory model to study the universe. A common feature of these unified model of the universe is full of space as the ideal fluid medium to treat, and the disturbance of are insulated. With the contradiction between the limitation of cosmological observations and theoretical model, some scholars suggest that the universe should consider non adiabatic medium disturbance. That is to say the universe may not be ideal fluid medium, but non ideal fluid containing a viscous. The viscous model for non adiabatic perturbation becomes the intrinsic attributes and more popular this paper mainly studies. The unified viscous fluid model of dark cosmological observations and limited volume viscosity formed by the impact of large scale structure in the universe. Firstly, cosmology's development history, research content and background knowledge. And then introduces the theory of cosmology model common astronomical observations and several major mainly. The research work of this thesis in the third chapter, the fourth chapter and the appendix. In the third chapter, a unified GCG model has the volume viscosity We first consider the disturbance type, volume viscosity. To limit the parameter space with the astronomical observation data of the model, get the new model parameters - volume viscosity coefficient in the range of 3 Sigma zeta 0 in value, and the influence of the evolution of the volume viscosity on the equation of state parameters and the effective adiabatic sound speed is discussed. In the fourth chapter. We investigate the VGCG model of the spherical collapse process, analysis and discussion of volume viscosity on the large scale structure of the universe formed (i.e. collapse) effect, and the results were compared with the results of the ACDM model. The last chapter is the summary and outlook. In addition, the appendix introduces the perturbation theory of Cosmology (including perturbation of volume viscosity the), and gives the specific derivation process density perturbations and velocity perturbation equations.

【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P159

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