宇宙学中的若干理论研究

The accelerated expansion of the universe is one of the frontier fields in physics and astronomy. The present proposal mainly focuses on (1) the issues relevant to the varying fundamental constants in cosmology. Note that the varying fundamental constants are closely linked to the two major approaches accounting for the accelerated expansion of the universe, namely dark energy and modified gravity theories. So, these issues are very important to understand the accelerated expansion of the universe. (2) the possible applications of Pade approximant in cosmology. In fact, Pade approximant can remedy the defects of Taylor series approximation, and hence it can greatly help to improve the studies of many issues in cosmology, such as luminosity distance, cosmography, and parameterization for equation of state. (3) the issues relevant to warm dark matter coexisting with dark energy. Recently, warm dark matter has risen as a serious alternative to cold dark matter. It is a good opportunity for significant developments and breakthroughs in this ongoing campaign. In addition to the above three topics, we will also keep attention to the traditional topics in cosmology, and try to find new directions in this field. The present proposal has many new features and creative ideas. The topics considered in this proposal are very important and interesting. Based on our previous works and achievements, we are qualified to ensure that the goals of this proposal will be achieved finally.

宇宙正在经历的加速膨胀是目前物理学和天文学的重要前沿领域。本面上项目主要集中于（1）深入研究宇宙学中与可变基本常数相关的课题。可变基本常数与当前宇宙加速膨胀的两大主流解释（暗能量、修改引力理论）密切相关；对可变基本常数的研究对于理解当前宇宙加速膨胀有重要的意义。（2）深入研究 Pade 近似在宇宙学中的应用。Pade 近似可以弥补泰勒级数近似的缺陷，对宇宙学若干方向（例如光度距离、cosmography 和态方程参数化等等）的改进发展有很大帮助。（3）深入研究温暗物质与暗能量共存情况下的相关课题。最近温暗物质崛起成为冷暗物质的强有力竞争者；这方面的研究方兴未艾，正是取得重要进展和突破的机会。我们在推进以上三个方面研究的同时持续关注宇宙学的传统研究课题，并寻找新的突破方向。本面上项目具有许多特色与创新，有相当大的科学意义。我们有足够的基础与前期积累来确保本面上项目的研究内容和目标能够实现。

1998 年发现的宇宙加速膨胀至今仍然是物理学和天文学的前沿领域之一。宇宙加速膨胀的本质仍然不清楚，包括暗能量模型、修改引力理论在内的多种可能性仍在互相竞争发展中。本项目主要研究宇宙学中若干理论问题，特别是与暗能量、修改引力相关的课题。在这些方向所取得的进展对于理解宇宙加速膨胀有重要的作用。在获得本项目资助的 2016—2019 年度，我们按计划进行研究，至今共计已在国际一流学术期刊正式发表 17 篇 SCI 高水平论文；这些论文均明确标注为本基金项目资助。本项目负责人韦浩在获得本项目资助的这四年中连续每年都入选 Elsevier 中国高被引学者榜单。我们在例如 Pade 近似在宇宙学中的应用、可变基本常数（尤其是精细结构常数和宇宙学常数等等）、洛伦兹不变性破坏、暗能量与暗物质相互作用、温暗物质、修改引力理论中的宇宙学和黑洞、宇宙结构增长历史、宇宙可能的各向异性、宇宙学模型的观测限制等等诸多方面进行了研究。这四年来我们在这些方面深入推进并取得了很好的进展，有助于深刻理解并解释这些问题。本项目所取得的成果都具有相当大的科学意义和学术价值。