Novel Directions in Physical Cosmology: Theory versus Observations

物理宇宙学的新方向：理论与观测

• 批准号: 436012-2013
• 负责人: Geshnizjani, Ghazal
• 金额: $ 1.53万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=574258
• 关键词: Novel; Directions; Physical; Cosmology; Theory

The unprecedented sensitivity and angular resolution of current and upcoming cosmological observations such as WMAP and Planck satellites provide us great opportunities to test cosmological theories. This makes it more urgent than ever that we are prepared with concrete models to infer properties of matter and gravity. A primary objective of this research program is to study the physics of the early universe which determines how our cosmos looks like today. An ideal theory of the early universe would be well-motivated from our understanding of fundamental physics, sets the right initial conditions for later stages of the cosmos without fine tuning, and also provides testable predictions that makes it falsifiable. Inflation, the most prominent paradigm of the early universe, still remains under scrutiny and needs to be confirmed or falsified. Finding the best strategy to achieve this ambition is one of the objectives of my research program, which has already produced valuable results. As experience has shown, inflationary models are quite forgiving in accommodating a variety of observational predictions. The novelty of my approach relies on using the knowledge we have from observation and theory in a new way to derive the characteristic features of the history of the early universe and investigate whether inflation can be confirmed. My research program also focuses on different aspects of modified gravity and dark energy models. The nature of dark energy is probably the most important question in astronomy today, and its discovery led to last year's Nobel prize in Physics. While, on the observational front, future experiments such as WFIRST Observatory and EUCLID are being planned, the theory is yet to be equipped with methods to interpret the data properly, in order to shed light on the nature of dark energy. The program that I am most interested to continue is finding optimum methods that can help us distinguish between different paradigms for apparent acceleration of cosmic expansion. A comprehensive approach would employ probes of cosmic geometry, as well as large scale structure formation, gravitational lensing observations and features in cosmic microwave background.

目前和即将到来的宇宙学观测，如WMAP和普朗克卫星，前所未有的灵敏度和角分辨率为我们提供了检验宇宙学理论的巨大机会。这使得我们比以往任何时候都更迫切地需要准备好具体的模型来推断物质和引力的性质。该研究计划的主要目标是研究早期宇宙的物理学，这决定了我们今天的宇宙是什么样子。一个理想的早期宇宙理论应该是基于我们对基础物理学的理解，为宇宙的后期阶段设定正确的初始条件而无需微调，并且还提供可检验的预测，使其成为可证伪的。 暴胀是早期宇宙最突出的范式，仍然处于审查之中，需要证实或证伪。找到实现这一目标的最佳策略是我的研究计划的目标之一，该计划已经产生了有价值的结果。经验表明，暴胀模型在适应各种观测预测方面是相当宽容的。我的方法的新奇依赖于以一种新的方式使用我们从观察和理论中获得的知识来推导早期宇宙历史的特征，并研究暴胀是否可以得到证实。 我的研究项目还侧重于修改后的引力和暗能量模型的不同方面。暗能量的本质可能是当今天文学中最重要的问题，它的发现导致了去年的诺贝尔物理学奖。虽然在观测方面，WFIRST天文台和欧几里得等未来实验正在计划中，但该理论尚未配备正确解释数据的方法，以揭示暗能量的性质。我最感兴趣的是继续寻找最佳方法，帮助我们区分宇宙膨胀明显加速的不同范式。一个全面的方法将利用宇宙几何学的探测，以及大尺度结构的形成，引力透镜观测和宇宙微波背景的特征。