半全息宇宙的研究

发布时间：2018-03-14 07:03

本文选题：暗物质　切入点：暗能量　出处：《上海师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：自从上个世纪九十年代发现宇宙加速膨胀以来,暗能量成为解释这种现象的最重要的理论。暗能量是能量的一种未知形式,它散布整个空间,并且能加速宇宙膨胀。科学家们通过研究发现,还一定存在另一种暗成分,即暗物质。暗物质是一种假设的物质,虽然无法直接看到,但它却是宇宙的主要物质。与普通物质相比,暗物质和暗能量在宇宙中占据了主要的地位。当今宇宙学里有一些问题仍未解决,其中一个是巧合性问题。为什么今天宇宙中的暗能量密度和暗物质密度几乎相等?本文的目的是探讨解决上述问题。本文首先介绍了Ted Jacobson对于时空热力学以及Stephen D.H.Hsu和David Reeb对于宇宙熵的研究。Ted Jacobson的研究开辟了一条途径来寻找除了黑洞以外其他情形下合适的全息表面。通过这个方法,我们发现表观视界就是宇宙正确的全息表面。而Stephen D.H.Hsu和David Reeb的研究则表明,根据全息原理所得到的宇宙的熵远远大于现在宇宙中已知物质的熵。所以假设宇宙中暗成分遵守全息原理,我们将会得到一些有趣的结论。然后,我们利用全息原理提出了一个新的宇宙模型,即半全息宇宙。假设宇宙中的暗能量遵守全息原理,则它的熵是表观视界的四分之一。由于存在可靠的证据表明,在暴涨后宇宙在共动体积内是绝热演化的,所以再根据热力学第一定律,我们会得出一定存在另外一种暗成分作为暗能量的补充。通过动力学系统分析会发现,宇宙晚期中的暗物质和暗能量的比例是稳定的。取恰当的参数,得到的减速因子可以很好地与现代观测结果一致。其中,由于重子物质所占的比例及其小,所以可以忽略掉。最终我们会发现,不管是在温度迅速变化的宇宙或温度缓慢变化的宇宙,暗物质和暗能量的有效状态方程的演化是相同的。这有助于更好地解决巧合性问题。并且,可以预言全息原理在早期宇宙中也有着很重要的影响。
[Abstract]:Since the discovery of the accelerating expansion of the universe in -10s, dark energy has become the most important theory to explain this phenomenon. Dark energy is an unknown form of energy that spreads throughout space. And it accelerates the expansion of the universe. Scientists have found that there must be another dark component, dark matter. Dark matter is a hypothetical substance, though it can't be seen directly. But it is the main substance of the universe. Dark matter and dark energy occupy a dominant position in the universe compared with ordinary matter. There are still some problems in cosmology today. One of them is coincidental. Why is the density of dark energy and dark matter almost equal in the universe today? The purpose of this paper is to solve the above problems. Firstly, this paper introduces the thermodynamics of space-time by Ted Jacobson and the study of cosmic entropy by Stephen D.H.Hsu and David Reeb. Ted Jacobson opens up a way to find the situation other than black hole. Form the appropriate holographic surface. By this method, We find that the apparent horizon is the correct holographic surface of the universe, while Stephen D. H. Hsu and David Reeb show that. The entropy of the universe based on the holographic principle is much larger than that of the known matter in the universe today. So assuming that the dark components of the universe follow the holographic principle, we will get some interesting conclusions. We propose a new cosmic model, the semi-holographic universe, based on the holographic principle. Assuming that the dark energy in the universe obeys the holographic principle, its entropy is 1/4 of the apparent horizon. The universe is adiabatic in the coaction volume after the explosion, so according to the first law of thermodynamics, we can conclude that there must be another dark component as a supplement to the dark energy. The proportion of dark matter and dark energy in the late universe is stable. With the appropriate parameters, the deceleration factor can be obtained in good agreement with modern observation results. So we can ignore it. Eventually we'll find out whether it's in a universe where the temperature is changing rapidly or in the universe where the temperature is slowly changing. The evolution of the effective equation of state for dark matter and dark energy is the same, which helps to solve the coincidental problem better. Furthermore, it can be predicted that the holographic principle also has an important influence in the early universe.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P159

【共引文献】