Explorations in Early Universe Cosmology and Dark Matter

该奖项资助匹兹堡大学物理系丹尼尔·博亚诺夫斯基教授的研究活动。通过对宇宙微波背景和星系的观察，我们对早期和现在宇宙的理解发生了革命性的变化，支持了膨胀宇宙学的主要范式：原始起源的量子力学涨落孕育了星系的形成。这些观测，加上希格斯玻色子的发现和对强相互作用和弱电弱相互作用理论的实验证实，证实了宇宙学和粒子物理的标准模型。伴随着这些发现，新的具有挑战性的方面出现了：宇宙中95%的能量密度以暗物质和暗能量的形式存在。此外，中微子，自然界中最难以捉摸的粒子，被发现是质量大的，并在不同类型之间进行混合和振荡-这是标准模型之外的现象。这些发现带来了前所未有的粒子物理学、天体物理学和宇宙学的融合，其中对星系的观测以及加速器和反应堆实验将产生超出标准模型的见解，一种新的中微子物种可能会解释暗物质。博亚诺夫斯基教授的研究计划在两个方面寻求基本的理解：(I)作为可能的暗物质候选者的一种新的中微子的产生和性质，以及(Ii)对原始宇宙中产生的最终孕育星系形成的量子涨落的更坚定的评估。该计划处于粒子天体物理学和宇宙学的前沿，补充了强有力的实验和观测努力，并真正是跨学科的，因为它实施了物理学其他领域的方法。因此，这些领域的研究通过促进科学进步来促进国家利益，这是最基本和最具启发性的努力之一，具有深刻的学术价值：发现新现象，从最小的组成部分开始理解我们宇宙的演化和星系的起源。通过这种概念和方法的交叉培养，这个研究项目也为学生提供了更广阔的视角和独特的机会，获得真正的跨学科教育体验。具体地说，博亚诺夫斯基教授将通过运用非平衡量子场论和量子动力学的方法，研究早期宇宙早期中微子新物种的产生、演化和引力聚集的机制。这些强大的方法将允许对作为暗物质候选者的新中微子物种进行系统评估。在宇宙学方面，该计划将专注于更深入地了解早期宇宙暴涨阶段的量子过程和关联。特别是，博亚诺夫斯基教授将研究相互作用和通货膨胀前和通货膨胀后的动态变化的波动频谱的修改，以及它们通过即将到来的观测发现的可能性。研究快速通货膨胀时期的过程需要新的工具。基于借用量子光学概念的新方法，如量子主方程和非平衡有效场论，将为可能的观测结果提供更深层次和更根本的评估。

This award funds the research activities of Professor Daniel Boyanovsky at the Department of Physics, University of Pittsburgh. Our understanding of the early and present Universe has been revolutionized by observations of the Cosmic Microwave Background and galaxies, supporting the main paradigm of inflationary cosmology: quantum-mechanical fluctuations of primordial origin seed the formation of galaxies. These observations, along with the discovery of the Higgs Boson and the experimental confirmation of the theory of strong and electroweak interactions, confirm the Standard Models of Cosmology and Particle Physics. Along with these discoveries new challenging aspects emerge: 95% of the energy density in the Universe is in the form of Dark Matter and Dark Energy. Furthermore, neutrinos, the most elusive particles in nature, are found to be massive and undergo mixing and oscillations among the different types --- a phenomenon beyond the Standard Model. These discoveries bring an unprecedented convergence of particle physics, astrophysics, and cosmology in which observations of galaxies along with accelerator and reactor experiments will yield insights beyond the Standard Models, with the tantalizing possibility that a new species of neutrinos may explain Dark Matter. Professor Boyanovsky's research program seeks a fundamental understanding on two fronts: (i) the production and properties of a new species of neutrinos as possible Dark-Matter candidates, and (ii) a firmer assessment of the quantum fluctuations generated in the primordial Universe that ultimately seed the formation of galaxies. The program is at the forefront of particle astrophysics and cosmology, complements robust experimental and observational efforts, and is truly interdisciplinary as it implements methods from other fields in physics. Research in these areas thus advances the national interest by promoting the progress of science in one of the most fundamental and stimulating endeavors of deep intellectual merit: the discovery of novel phenomena and the understanding of the evolution of our Universe and the origin of galaxies beginning from the smallest constituents. Through this cross-fertilization of concepts and methods, this research program also provides students with a broader perspective and unique opportunity to acquire a truly interdisciplinary educational experience. Specifically, Professor Boyanovsky will study mechanisms for production, evolution, and gravitational clustering of new species of neutrinos during the early stages of the Early Universe by implementing methods from out-of-equilibrium quantum field theory and from quantum kinetics. These powerful methods will allow a systematic assessment of the new species of neutrinos as a Dark-Matter candidate. In cosmology, the program will focus on a deeper understanding of quantum processes and correlations during the inflationary stage in the early Universe. In particular, Professor Boyanovsky will study modifications of the spectrum of fluctuations from interactions and pre- and post-inflationary dynamics and their potential for detection with forthcoming observations. The study of processes during the period of rapid inflationary expansion requires novel tools. New methods based on concepts borrowed from quantum optics, such as quantum master equations, and out-of-equilibrium effective field theory, will provide a deeper and more fundamental assessment of possible observational consequences.