新的广义Chaplygin气体模型及其相关问题的研究

发布时间：2018-06-08 17:30

本文选题：暗能量 + 正压背景流体　；参考：《辽宁师范大学》2011年硕士论文

【摘要】：随着对Ia超新星、宇宙做波背景辐射以及大尺度结构等的观测表明当前宇宙正处于加速膨胀状态。天文观测还表明宇宙中各组分的比例大致为：73％的暗能量，23％的暗物质和4％的重子物质。暗能量所占比例很大，是当前宇宙的重要组成部分。为了更加科学的研究宇宙，，几们建立了大量的宇宙学模型，最简单的暗能量模型是宇宙学常数。常见的暗能量模型还有：Quitessence，Phantom，Tachyon，K-essence，全息暗能量，Chaplygin气体(CG)及其推广模型等。对于CG及它的推广模型，其最吸引几的性质在于能将宇宙中两个不可见的暗部分(即暗物质和暗能量)巧妙地统一起来。其中研究最广泛的是广义Chaplygin气体(GCG)模型。新的广义Chaplygin气体(NGCG)模型作为GCG模型的推广也被建立。该模型包含了暗能量态参数为常数的情行，其早期行为类似于暗物质，而晚期类似于宇宙学常数。本文将主要讨论NGCG流体与正压背景流体之间存在相互作用(相互作用项取为Q = 3Hc(ρ_(NGCG)+ρ_γ))时动力学系统的稳定性问题。通过对NGCG模型动力学自洽系统的讨论，得到了该动力学系统的临界点，进而求得了该模型的吸引子。进一步，文中描绘了该模型中相关宇宙学量的演化，即NGCG流体态参数、无量纲密度参数及声速的演化。最后，文中对NGCG模型进行了Om几何诊断，将该模型的Om曲线与ΛCDM的Om曲线做对比，直观地展示了二者之间的差异。
[Abstract]:With the observation of Ia supernova, cosmic background radiation and large scale structure, it is shown that the universe is in the state of accelerating expansion. Astronomical observations also show that the proportion of components in the universe is approximately: 73% dark energy 23% dark matter and 4% baryon matter. Dark energy accounts for a large proportion and is an important part of the current universe. In order to study the universe more scientifically, many cosmological models have been established, and the simplest dark energy model is cosmological constant. The common dark energy models include: Q Q Phantomo Tachyon K-essence, holographic dark energy Chaplygin gas (CGG) and its generalized model. Its most attractive nature is the ability to neatly unify two invisible dark parts of the universe, namely dark matter and dark energy. The generalized Chaplygin gas GCGmodel is the most widely studied. A new generalized Chaplygin gas NGCGG model is also established as a generalization of the GCG model. The model contains constant dark energy state parameters and its early behavior is similar to that of dark matter. In this paper, we mainly discuss the stability of the dynamical system when the interaction between NGCG fluid and barotropic background fluid is Q = 3Hc (蟻 _ S / NGCG蟻 _ 纬). By discussing the dynamical self-consistent system of NGCG model, the critical point of the dynamic system is obtained, and the attractor of the model is obtained. Furthermore, the evolution of the relevant cosmological quantities in the model, namely, the evolution of NGCG flow state parameters, dimensionless density parameters and sound velocity, is described in this paper. Finally, the Om geometric diagnosis of NGCG model is carried out, and the Om curve of this model is compared with that of A CDM, and the difference between them is shown intuitively.
【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】：P159

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