宇宙拓扑缺陷于暗能量 Alternative Title Cosmic Topological Defects and Dark Energy 赵振华 Thesis Advisor 段一士 2005-05-31 Degree Grantor 兰州大学 Place of Conferral 兰州 Degree Name 硕士 Keyword 宇宙拓扑缺陷 暗能量 Abstract 本文利用段一士教授提出的Φ－映射拓扑流理论，研究了宇宙论中的四种拓扑缺陷，并证明了一种广义的序参量场可以构成暗能量并提供负压。 我们首先介绍本论文所需的预备知识，如隐函数定理、U(1)规范势分解和Φ－映射拓扑流理论，这是我们处理拓扑缺陷的理论基础。认识到在序参量场的零点处，可以自然的产生各种拓扑缺陷，而且缺陷的种类由序参量场的维数决定。接着我们介绍了宇宙论的基础知识，包括R-W度规、宇宙动力学方程、Doppler频移和宇宙大尺度测量等，这是理解宇宙现象和研究暗能量的基础。 我们具体讨论了序参量场作为宇宙中暗能量的模型，对于理论的体系给出了完整的表述。我们从序参量场的拉氏量密度 出发，推导出了其能动张量，然后我们得到了其密度和压强。取一定的近似其密度和压强的比值为负一，这就证明了一种广义的序参量场可以作为暗能量并提供使宇宙加速膨胀的负压力。利用Φ－映射拓扑流理论我们讨论了四维时空中，由上述序参量场可能产生的四种拓扑缺陷，它们是不同维数的序参量场在其零点处产生的，有时空的畴壁、单极、宇宙弦和纹理。 Other Abstract In this dissertation, we have studied four kinds of cosmic defects using Φ-mapping topology current theory，which is proposed by Prof. Yi-shi Duan, and proved that one general order parameter field can compose the dark energy and provide the negative press. We first introduced the implicit function theorem, the decomposition of U(1) gauge potential and Φ-mapping topology current theory as a foundation for the exploring of topological defects. So we could get that the topological defects were produced from the zero points of the order parameter field naturally. And the class of defects is decided by the dimension of the order parameter field. Later we introduced the foundation of the cosmology, including R-W metric, cosmic dynamics equation, Doppler frequency shift and the measure of large scale in universe, which is needed for understanding the phenomenon of the universe and dark energy. We mainly studied the model of dark energy with general order parameter field in detail, and we gave a whole expression of this theory. From the order parameter field's density of Lagrange , we get the energy momentum tensor of it. And we derived the density and pressure intensity from energy momentum tensor. The ratio for density and pressure intensity would changed to -1, if we used it's approximation. So we could prove that one kind of general order parameter field can act as dark energy and provide the negative press for the accelerating of cosmic inflation. Four topology defects were investigated using Φ-mapping topology current theory. These defects are domain wall, monopole, cosmic string and texture, and they are all produced from the zero points of order parameter field. URL 查看原文 Language 中文 Document Type 学位论文 Identifier https://ir.lzu.edu.cn/handle/262010/229034 Collection 物理科学与技术学院 Recommended CitationGB/T 7714 赵振华. 宇宙拓扑缺陷于暗能量[D]. 兰州. 兰州大学,2005.
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