Sub-systems and Correlations in Cosmology and Particle Physics

这项拨款资助了宾夕法尼亚州立大学的Sarah Shandera教授的研究活动。通过观察宇宙学现象，物理学家研究了能量尺度上许多数量级的基本力（包括引力）。 通过这种方式，并由于与地面对撞机实验的互补性，我们在理解宇宙方面取得了许多成功。 不幸的是，最令人困惑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。 这些情况涉及的基本能量尺度使得在可预见的未来不可能进行实验室测试。 作为她的研究活动的一部分，Shandera教授将开发一个框架，用于对基本物理定律进行强有力的推断，正确解释宇宙学中固有但并非唯一的不确定性类型。 与她的研究生一起，她将研究早期宇宙的理论，其中不可观测的物理学可能会增加模型的不确定性。 她将研究这个问题的经典和量子两个方面。 这些研究将通过促进我们对物理定律的基本理解和发现来促进国家利益。 Shandera教授将通过为初中和高中学生和教师举办的研讨会，让她的研究生参与向公众传播宇宙研究的方法和结果。更具体地说，Shandera教授将研究宇宙学和粒子物理学中的系统，其中只有一个随机或量子力学自由度的子集是可观测的，并且该子系统与未观测到的模式相耦合。 她将（1）从即将进行的宇宙微波背景极化观测和大尺度结构调查中，探讨从次哈勃模式耦合到超哈勃模式的宇宙变化如何影响对暴胀时代的推断;（2）研究长短模式耦合系统中的量子相关性，以及追踪长波长模式的短波长模式的有效理论;以及（3）利用多场暴胀研究中的已知问题和结果来探索其他量子子系统的有效理论，其中相关的未观测模式不需要是高能模式。

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.