CAREER: Non-equilibrium Many-Body Dynamics in Topological Quantum Materials

非技术总结这个职业奖项支持拓扑材料的理论研究和教育。近年来，由于拓扑材料不同寻常的量子行为和它们承诺实现的新技术，拓扑材料的研究出现了爆炸性增长。由于它们的拓扑性质，这种材料可以承载需要相对较少的功率来驱动的电流，并且在某些情况下，可以通过施加光或磁场来激活这些电流。拓扑材料的这些特性使它们成为目前正在追求的重要应用的候选对象，包括新一轮的低功耗电子学、光电探测器和太阳能电池器件。要使这些技术成为现实，需要对其丰富的物理学有深刻的理解。这个项目的目标是开发新的理论技术，这些技术可以用来准确预测在外加电场、磁场或激光存在的情况下这些材料中的电流行为。然后，这些预测可以用来指导新的实验、技术应用的进一步进展，以及对拓扑材料和更广泛的材料的基本理解的进步。为了实现这些以及未来更多的技术进步，至关重要的是加强凝聚态物理和更广泛的STEM领域的劳动力。目前的预测表明，在这些领域获得学位的学生人数不足，无法维持目前的技术产出水平。该项目侧重于通过三种方式招收更多的学生进入STEM：(I)通过高中系列讲座让学生更好地了解该领域和相关的职业道路；(Ii)为高中和本科生提供研究机会；(Iii)指导研究生和本科生为STEM职业生涯做准备。这些努力将特别强调加强多样性。技术总结这个职业奖支持拓扑材料的理论研究和教育。研究部分解决与驱动拓扑材料中的自旋、谷或电荷的传输有关的基本问题。尽管有巨大的兴趣和快速的进展，但由于问题的非平衡、多体性质，这些过程的许多基本物理仍然不清楚。PI旨在通过开发基于先进技术的理论来阐明这些过程，这些理论使人能够在不牺牲可计算性的情况下保留关于系统和浴液的随时间变化的信息。该项目的主要目标包括：(I)解释拓扑量子材料中的非平衡和多体现象。主要研究了拓扑绝缘体和过渡金属二卤化物中的光驱动和极化自旋注入，以及Weyl半金属中的手性反常输运。(2)发展关于外部驱动下产生的动态反馈机制的理论。该理论将使用广义主方程、动力学映射和其他技术来跟踪两个载流子及其量子环境的演变。将设计控制浴缸的方法，以减轻不利影响并开发新的技术能力。所开发的技术将适用于广泛的多体系统。(Iii)结合多体理论和非平衡理论，理解强库仑相互作用和拓扑结构在二维材料中自旋和谷极化输运以及三维半金属中反常电荷输运中的相互作用。(4)制定推广方案，招收更多学生进入STEM领域，包括量子凝聚态物理。这将包括高中系列讲座和为本科生和高中生提供的研究实习。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis CAREER award supports theoretical research and education on topological materials. Recent years have witnessed an explosion in research on topological materials spurred by their unusual quantum behavior and by the novel technologies they promise to enable. Such materials can host currents that require relatively little power to drive due to their topological properties, and in some cases these currents can be activated by applying light or magnetic fields. These features of topological materials make them candidates for important applications currently pursued including a new wave of low-dissipation electronics, photodetectors, and solar cell devices. Making these technologies a reality requires a deep understanding of their rich physics. The goal of this project is to develop new theoretical techniques that can be used to make accurate predictions about the behavior of currents in these materials in the presence of applied electric fields, magnetic fields, or lasers. These predictions could then be used to guide further progress toward new experiments, technological applications, and advances in fundamental understanding of topological materials and materials more generally. To realize these and many more technological advances going forward, it is crucial to strengthen the workforce in condensed matter physics and more broadly in STEM fields. Current projections indicate that insufficient numbers of students are obtaining degrees in these fields to maintain present technological output levels. This project focuses on recruiting more students to STEM in three ways: (i) By giving students a better understanding of the field and related career paths through high school lecture series; (ii) By providing research opportunities to high school and undergraduate students; (iii) By mentoring graduate and undergraduate students to prepare them for STEM careers. These efforts will be carried out with a particular emphasis on strengthening diversity.TECHNICAL SUMMARYThis CAREER award supports theoretical research and education on topological materials. The research component addresses fundamental questions pertaining to the transport of spin, valley, or charge in driven topological materials. Despite enormous interest and rapid progress, much of the basic physics of these processes remains unclear due to the non-equilibrium, many-body nature of the problem. The PI aims to shed light on these processes by developing theories based on advanced techniques that enable one to retain time-dependent information about both system and bath without sacrificing calculability. The main goals of the project include: (i) Explain non-equilibrium and many-body phenomena in topological quantum materials. Primary focus is given to optical driving and polarized spin injection in topological insulators and transition metal dichalcogenides, and to chiral anomalous transport in Weyl semimetals. (ii) Develop a theory of dynamic feedback mechanisms that arise under external driving. This theory will employ generalized master equations, dynamical maps, and other techniques to track the evolution of both carriers and their quantum environment. Methods for controlling the bath will be devised to mitigate adverse effects and develop new technological capabilities. The developed techniques will be applicable to a broad range of many-body systems. (iii) Understand the interplay of strong Coulomb interactions and topology in the transport of spin and valley polarization in 2D materials and in anomalous charge transport in 3D semimetals by combining many-body and non-equilibrium theory techniques. (iv) Develop an outreach program that recruits more students into STEM fields, including quantum condensed matter physics. This will consist of high school lecture series and research internships for undergraduate and advanced high school students.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.