Cosmological tests of fundamental physics

我们生活在宇宙学的黄金时代。下一代光学和射电望远镜将完成宇宙结构的详细三维地图，揭示其在多个时代的演变。即将到来的宇宙微波背景（CMB）实验将产生高质量的极化图，有可能证实初始不均匀性的量子起源，这种不均匀性为恒星和星系的形成埋下了种子。加拿大天文学家积极参与这些努力。我的提议是受到即将到来的实验提供的机会的启发，这些实验将解决粒子物理学和宇宙学中一些长期存在的难题，比如暗物质和暗能量的本质。在与观测团队密切合作的同时，我的团队在巩固其在设计和应用基础物理新测试方面的领导地位方面处于有利地位。我提出的研究计划大致分为两个主题：一个是关注晚时间宇宙的动力学，包括对暗能量的研究，广义相对论的宇宙学测试和引力的替代理论。另一个将涉及早期宇宙，并将宇宙学作为测试粒子物理学的实验室。暗物质和暗能量占宇宙能量的95%，而广义相对论在宇宙时间和距离上的检验也很弱，因此人们对发展和检验引力的替代理论非常感兴趣。我的小组将开发理论框架和数值工具，除了测试暗能量和修正引力的特定理论外，还将以尽可能独立于模型的方式回答一系列重要的定性问题。这些问题将包括暗能量密度是否在时间上保持恒定，等效原理是否在宇宙尺度上成立，以及暗成分之间是否存在相互作用。我们的工作将建立在与即将到来的DESI， Euclid和LSST等调查团队成员现有的长期合作基础上。不断膨胀的宇宙就像一台显微镜，揭示了粒子加速器无法达到的能量下的物理现象。CMB一直是我们的主要信息来源，最终将由未来实验（如LISA）的引力波（GW）观测补充。这一提议包括研究早期宇宙中发生的相变，以及它们的遗迹，如原始磁场和宇宙弦，以及它们的特征CMB和GW特征。我也会研究轴子弦和它们向暗物质的衰变。我在这方面的工作将构成我对CMB-S4合作的一部分贡献。SFU宇宙学组结合了理论、统计、计算和数据分析方面的专业知识，为开发和测试新想法提供了一个刺激的环境，并为在积极的国际兴趣领域培训HQP提供了独特的机会。

We live in a golden age of cosmology. The next generation of optical and radio telescopes will complete the detailed 3D map of the structure in the universe, revealing its evolution through multiple epochs. Upcoming cosmic microwave background (CMB) experiments will produce high quality polarization maps potentially confirming the quantum origin of the initial inhomogeneities that seeded formation of stars and galaxies. Canadian astronomers are actively involved in these efforts. My proposal is inspired by the opportunities presented by the upcoming experiments for resolving some of the long-standing puzzles in particle physics and cosmology, such as the nature of dark matter and dark energy. My group is in a good position to solidify its leading role in designing and applying new tests of fundamental physics, while working in close partnership with observational teams. The research program I propose is broadly grouped into two main themes: One focuses on the dynamics of the late time universe and includes studies of dark energy, cosmological test of general relativity and alternative theories of gravity. The other will concern the early universe and using cosmology as a laboratory for testing particle physics. With dark matter and dark energy making up 95% of the energy content of the universe, and with general relativity only weakly tested over cosmological times and distances, there is a considerable interest in developing and testing alternative theories of gravity. My group will develop theoretical frameworks and numerical tools that, in addition to testing specific theories of dark energy and modified gravity, will answer a set of important qualitative questions in as model-independent way as possible. Such questions would include whether dark energy density remains constant in time, whether the equivalence principle holds on cosmological scales and if there are interactions between the dark components. Our work will build on existing long term collaborations with team members of upcoming surveys such as DESI, Euclid and LSST. The expanding universe acts as a microscope revealing physics at energies beyond the reach of particle accelerators. CMB has been our key source of information that will eventually be complemented by gravitational wave (GW) observations from future experiments such as LISA. This proposal includes studying the phase transitions that took place in the early universe, along with their relics, such as primordial magnetic fields and cosmic strings, and their characteristic CMB and GW signatures. I will also study axion strings and their decay into dark matter. My work in this area will form part of my contribution to the CMB-S4 collaboration. The SFU Cosmology Group, with its combined expertise in theory, statistics, computing and data analysis, provides a stimulating environment for developing and testing new ideas, and unique opportunities for training HQP in areas of active international interest.