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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=678488
• 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.

WMAP和Planck卫星等当前和即将到来的宇宙学观察结果的前所未有的灵敏度和角度分辨率为我们提供了测试宇宙理论的绝佳机会。这比以往任何时候都更加紧迫，我们准备使用混凝土模型来推断物质和重力的特性。该研究计划的主要目的是研究早期宇宙的物理学，这决定了我们的宇宙今天的样子。从我们对基本物理学的理解中，早期宇宙的理想理论将得到充分激励，为宇宙的后期阶段设定了正确的初始条件，而无需进行微调，还提供了可检验的预测，使其可伪造。通货膨胀是早期宇宙中最突出的范式，仍处于审查状态，需要确认或伪造。找到实现这一野心的最佳策略是我的研究计划的目标之一，该计划已经产生了宝贵的结果。正如经验所表明的那样，通货膨胀模型在适应各种观察性预测时非常宽容。我的方法的新颖性依赖于我们从观察和理论中获得的知识以一种新的方式来得出早期宇宙历史的特征，并研究是否可以证实通货膨胀。黑暗能源的本质可能是当今天文学中最重要的问题，其发现导致了去年的诺贝尔物理学奖。尽管在观察方面，正在计划未来的实验，例如WFIRST观测和欧几里得，但该理论尚未配备正确解释数据的方法，以阐明黑暗能量的性质。我最感兴趣的程序是找到最佳方法，可以帮助我们区分不同的宇宙扩展加速范式。一种全面的方法将采用宇宙几何形状的探针，以及大规模结构形成，重力镜头观测和宇宙微波背景中的特征。