Physics of Non-Fermi Liquid Metals

非技术总结：该奖项支持强相关量子材料物理学的理论研究和教育。虽然教科书对固体中电子的描述在描述传统金属（如铝）和简单半导体（如硅）方面取得了巨大成功，但它对本质上独立的电子的依赖已被证明不适用于广泛的量子材料。这种材料中的电子不能被认为是彼此独立运动的，因为它们彼此之间具有很强的相关性。这种相关性可以产生新的量子相，并在绝对零度温度下引起相变。这些是我们熟悉的相变的量子模拟，比如水冻结成冰。在一类这样的量子相变中，电子以一种高度集体性的方式活动，形成了一种“奇怪的金属”行为。PI将应用或开发理论方法来研究这种奇怪的金属物理，在这种量子相变附近，包括一种电子流动没有任何能量损失（超导性）的相变，这可能与量子信息技术有关。从长远来看，从这些研究中获得的基础知识可以帮助在量子计算、量子传感和计量领域取得重大技术进步。这项研究将为博士后、研究生和本科生创造培训机会，他们将成为量子科学和技术领域未来的劳动力。该奖项还将支持编写一本关于“重费米子和量子相变”的书，供研究生学习一个学期的课程。PI将通过撰写评论文章和组织研讨会来传播量子材料领域的研究进展，这将有助于教育和培训凝聚态物理前沿主题的年轻科学家和学生。该奖项支持强相关量子系统物理学的理论研究。总体目标是了解强相关性如何导致金属系统中不寻常的激发和新的量子相。PI将应用和发展受控的理论方法来研究定义良好的理论模型。具体研究方向有四个。首先，将分析重费米子量子临界性，重点关注以奇异电荷响应为特征的新体制。其次，PI将启动在量子临界点附近出现的新相的理论研究，特别关注候选自旋三重态超导性。第三，探索Weyl-Kondo半金属体系中的非费米液体物理。第四，PI将研究量子临界系统的非平衡物理。这项研究将为博士后、研究生和本科生创造培训机会，他们将成为量子科学和技术领域未来的劳动力。该奖项还将支持编写一本关于“重费米子和量子相变”的书，供研究生学习一个学期的课程。PI将通过撰写评论文章和组织研讨会来传播量子材料领域的研究进展，这将有助于教育和培训凝聚态物理前沿主题的年轻科学家和学生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARY:This award supports theoretical research and education on the physics of strongly correlated quantum materials. While the textbook description of electrons in solids has been enormously successful in describing conventional metals such as Aluminum and simple semiconductors such as Silicon, its reliance on essentially independent electrons has proven to be inadequate for a broad range of quantum materials. Electrons in such materials cannot be considered to move independent of each other, as they experience strong correlations with each other. Such correlations can produce novel quantum phases and give rise to phase transitions at the absolute zero of temperature. These are quantum analogues of familiar phase transitions such as water freezing into ice. In a class of such quantum phase transitions, electrons act in a highly collective way and a “strange-metal” behavior develops. The PI will apply or develop theoretical methods to study this strange-metal physics near such quantum phase transitions including a type of a phase in which electrons flow without any loss of energy (superconductivity) that may be relevant for quantum information technologies. The fundamental knowledge gained from these studies could, in the long run, help in significant technological advances in the areas of quantum computation, quantum sensing and metrology. The research will create training opportunities for postdocs, graduate students, and undergraduate students who will form the future workforce in quantum science and technology. This award will also support the preparation of a book on "Heavy Fermions and Quantum Phase Transitions" intended for graduate students taking a one-semester course. The PI will disseminate research advances in the area of quantum materials by writing review articles and organizing workshops, which will help in educating and training junior scientists and students in topics at the forefront of condensed matter physics.TECHNICAL SUMMARYThis award supports theoretical research in the physics of strongly correlated quantum systems. The general goal is to understand how strong correlations lead to unusual excitations and novel quantum phases in metallic systems. The PI will apply and develop controlled theoretical methods to study well-defined theoretical models. Four specific research directions will be pursued. First, heavy fermion quantum criticality will be analyzed, with a focus on new regimes characterized by singular charge responses. Second, the PI will initiate theoretical studies on the novel phases that emerge near quantum critical points, with a particular focus on candidate spin-triplet superconductivity. Third, non-Fermi liquid physics in Weyl-Kondo semimetal systems will be explored. Fourth, the PI will investigate out-of-equilibrium physics of quantum critical systems. The research will create training opportunities for postdocs, graduate students, and undergraduate students who will form the future workforce in quantum science and technology. This award will also support the preparation of a book on "Heavy Fermions and Quantum Phase Transitions" intended for graduate students taking a one-semester course. The PI will disseminate research advances in the area of quantum materials by writing review articles and organizing workshops, which will help in educating and training junior scientists and students in topics at the forefront of condensed matter physics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.