全息暗能量模型的整体拟合研究
发布时间：2019-07-02 13:33
【摘要】：历史上宇宙膨胀的发现从根本上变革了人们之前对宇宙静态而永恒的认识,从而直接促使了“热大爆炸”宇宙学说的建立。近年来宇宙加速膨胀的发现则改变了人们对宇宙中物质特性的理解,从而引起了对暗能量的研究热潮。天文观测的发展为研究现代宇宙学中暗能量等重要问题提供了很好的契机。当前,利用众多的观测联合对包括暗能量在内的宇宙学模型做参数限制已经成为宇宙学中标准的研究方法。特别是使用宇宙微波背景辐射(CMB)观测的全部信息对暗能量模型做整体拟合研究越来越受到人们的重视。本文重点对全息暗能量(HDE)和新年刻暗能量(NADE)两类全息暗能量模型进行观测上的整体拟合分析。在对HDE模型整体拟合分析中,考虑宇宙空间曲率和有质量中微子对HDE演化的影响,采用paxameterized post-Friedmann方法处理HDE模型在ω越过-1时存在的密度扰动发散的问题。我们发现考虑空间曲率可以大大降低HDE模型中参数e1的置信度,表明考虑空间曲率有助于缓解HDE模型的未来宇宙“大撕裂”问题。同时我们首次在HDE模型中得到了中微子质量总和的上限。我们还从理论上研究了HDE模型中唯象参数c对宇宙背景演化、物质密度扰动演化、CMB功率谱及大尺度结构增长的影响。从中我们发现当c(?)0.7时,HDE模型与标准的ACDM模型得到几乎相同的结果。在对NADE模型的研究中,我们首次对其做了整体拟合分析,并讨论了该模型的初始条件问题,得到了一个能够在考虑辐射及空间曲率的宇宙当中适用的新初始条件。拟合结果显示在新初始条件下,NADE模型可以被限制得很好,该模型偏好于一个负的空间曲率Ωk0。此外拟合得到的NADE模型中参数n的最佳拟合值比以往工作中得到的结果要偏小,经过深入分析,我们发现这一变化由超新星观测数据使用上的不同导致,且我们得到的NADE模型的最新拟合结果比以往的结果更为合理。
[Abstract]:The discovery of cosmic expansion in history fundamentally changed people's previous understanding of the static and eternal universe, thus directly promoting the establishment of the theory of the "hot explosion" universe. In recent years, the discovery of accelerated expansion of the universe has changed people's understanding of the properties of matter in the universe, which has led to an upsurge in the study of dark energy. The development of astronomical observation provides a good opportunity for the study of dark energy in modern cosmology. At present, it has become a standard research method in cosmology to use many observation combinations to limit the parameters of cosmological models, including dark energy. In particular, more and more attention has been paid to the whole fitting of dark energy model by using all the information observed by cosmic microwave background radiation (CMB). In this paper, two kinds of holographic dark energy models, holographic dark energy (HDE) and New year dark energy (NADE), are observed and analyzed. In the overall fitting analysis of HDE model, considering the influence of space curvature and mass neutrino on the evolution of HDE, the paxameterized post-Friedmann method is used to deal with the divergence of density disturbance in HDE model over-1. It is found that considering spatial curvature can greatly reduce the confidence of parameter E1 in HDE model, which shows that considering spatial curvature is helpful to alleviate the "big tear" problem of HDE model in the future. At the same time, we obtain the upper limit of neutrino mass sum in HDE model for the first time. We also theoretically study the effects of phenomenological parameter c in HDE model on the evolution of cosmic background, the evolution of material density disturbance, the power spectrum of CMB and the growth of large-scale structure. It is found that when c (?) 0.7, the HDE model and the standard ACDM model get almost the same results. In the study of the NADE model, we do the global fitting analysis for the first time, discuss the initial conditions of the model, and obtain a new initial condition which can be applied in the universe considering radiation and spatial curvature. The fitting results show that the NADE model can be well limited under the new initial conditions, and the model prefers a negative spatial curvature 惟 k 0. In addition, the optimal fitting value of parameter n in the fitted NADE model is smaller than that in the previous work. After in-depth analysis, we find that this change is caused by the different use of supernova observation data, and the latest fitting results of the NADE model are more reasonable than the previous results.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P159
本文编号：2508975
[Abstract]:The discovery of cosmic expansion in history fundamentally changed people's previous understanding of the static and eternal universe, thus directly promoting the establishment of the theory of the "hot explosion" universe. In recent years, the discovery of accelerated expansion of the universe has changed people's understanding of the properties of matter in the universe, which has led to an upsurge in the study of dark energy. The development of astronomical observation provides a good opportunity for the study of dark energy in modern cosmology. At present, it has become a standard research method in cosmology to use many observation combinations to limit the parameters of cosmological models, including dark energy. In particular, more and more attention has been paid to the whole fitting of dark energy model by using all the information observed by cosmic microwave background radiation (CMB). In this paper, two kinds of holographic dark energy models, holographic dark energy (HDE) and New year dark energy (NADE), are observed and analyzed. In the overall fitting analysis of HDE model, considering the influence of space curvature and mass neutrino on the evolution of HDE, the paxameterized post-Friedmann method is used to deal with the divergence of density disturbance in HDE model over-1. It is found that considering spatial curvature can greatly reduce the confidence of parameter E1 in HDE model, which shows that considering spatial curvature is helpful to alleviate the "big tear" problem of HDE model in the future. At the same time, we obtain the upper limit of neutrino mass sum in HDE model for the first time. We also theoretically study the effects of phenomenological parameter c in HDE model on the evolution of cosmic background, the evolution of material density disturbance, the power spectrum of CMB and the growth of large-scale structure. It is found that when c (?) 0.7, the HDE model and the standard ACDM model get almost the same results. In the study of the NADE model, we do the global fitting analysis for the first time, discuss the initial conditions of the model, and obtain a new initial condition which can be applied in the universe considering radiation and spatial curvature. The fitting results show that the NADE model can be well limited under the new initial conditions, and the model prefers a negative spatial curvature 惟 k 0. In addition, the optimal fitting value of parameter n in the fitted NADE model is smaller than that in the previous work. After in-depth analysis, we find that this change is caused by the different use of supernova observation data, and the latest fitting results of the NADE model are more reasonable than the previous results.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P159
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