Sub-systems and Correlations in Cosmology and Particle Physics

这笔赠款资助了宾夕法尼亚州立大学萨拉·香德拉教授的研究活动。通过观察宇宙学现象，物理学家研究能量尺度上许多数量级的基本力(包括引力)。通过这种方式，多亏了与地面对撞机实验的互补性，我们在理解宇宙方面取得了无数成功。不幸的是，最令人费解的宇宙学现象是那些我们不能轻易用对撞机探索的现象，包括暗能量和大爆炸时代的物理学。这些案例中涉及的基本能量尺度使得实验室测试在可预见的未来是不可能的。作为她的研究活动的一部分，Shandera教授将开发一个框架，用于对潜在的物理定律进行稳健的推断，正确地解释宇宙学固有的、但不是唯一的不确定性类型。她将和她的研究生们一起学习早期宇宙的理论，在这种理论中，不可观测的物理可能会给模型增加不确定性。她将研究这个问题的经典和量子两个方面。这些研究将有助于我们在根本层面上理解和发现物理定律，从而促进国家利益。Shandera教授将让她的研究生通过为初中生和教师举办的研讨会向公众交流宇宙研究的方法和结果。更具体地说，尚德拉教授将研究宇宙学和粒子物理学中的系统，在这些系统中，只有随机或量子力学自由度的子集是可以观测到的，而且这个子系统与未观察到的模式相耦合。她将(1)探索从耦合的亚哈勃模到超哈勃模的宇宙差异如何影响从即将到来的宇宙微波背景偏振观测和大规模结构调查得出的关于暴涨时代的推断；(2)检查具有长短模耦合的系统中的量子关联，以及找到具有长波长模的短波长模的有效理论；以及(3)利用已知的问题和多场暴胀研究的结果，为其他量子子系统探索有效的理论，其中相关的未观测到的模不一定是高能模。

This grant funds the research activities of Professor Sarah Shandera at The Pennsylvania State University.By observing cosmological phenomena, physicists study the fundamental forces (including gravity) across many orders of magnitude in energy scale. In this way, and thanks to complementarity with terrestrial collider experiments, numerous successes in our understanding of the universe have been achieved. Unfortunately, the most puzzling cosmological phenomena are those that we cannot easily explore with colliders, including dark energy and the physics of the Big Bang era. The fundamental energy scales involved in those cases make laboratory tests impossible for the foreseeable future. As part of her research activities, Professor Shandera will develop a framework for robust inference of the underlying physical laws that correctly accounts for the types of uncertainty inherent in, but not unique to, cosmology. Together with her graduate students, she will study theories of the very early universe where unobservable physics may add uncertainty to the model. She will study both classical and quantum aspects of the problem. These studies will advance the national interest by contributing to our understanding and discovery of physical law at a fundamental level. Professor Shandera will involve her graduate students in communicating methods and results from the study of the universe to the public through workshops for middle- and high-school students and teachers. More specifically, Professor Shandera will study systems in cosmology and particle physics where only a subset of stochastic or quantum-mechanical degrees of freedom are observationally accessible, and where that subsystem is coupled to unobserved modes. She will (1) explore how cosmic variance from coupling sub-Hubble modes to super-Hubble modes can affect inference about the inflationary era from upcoming observations of the polarization of the cosmic microwave background and large-scale structure surveys; (2) examine the quantum correlations in systems with long-short mode coupling and effective theories for short-wavelength modes with the long-wavelength modes traced out; and (3) use known issues and results from studies of multi-field inflation to explore effective theories for other quantum subsystems where the relevant unobserved modes need not be high-energy modes.