Towards a Unified Framework of Quantum Dynamics of Nonlinear Optical and Transport Processes

非技术概述这个项目推进并拓宽了我们对强光下材料的基本科学理解。令人感兴趣的是物理定律与日常经验截然不同的现象和材料，因为材料内部的粒子很小，即量子物理和量子材料。提高我们对辐照量子材料的了解将促进它们在未来的量子技术中的使用，例如更高效的太阳能收集、更快的计算机和光电子应用。这项研究在光学和量子凝聚态物理方面都发展了新的概念和方法，使这两个领域的知识都受益。教育和外展努力包括开发一门新的计算物理课程，为高年级本科生(包括来自附近少数族裔服务机构的学生)举办一个研讨会，为参加向上跳跃课程的低收入高中生开发一个为期一天的STEM课程单元，通过美国国务院的国际教育领袖计划接待中学教师，以及指导本科生和研究生的研究。这些努力旨在扩大STEM的劳动力并使其多样化。技术概述对清洁能源的需求导致了人们对太阳能收集的极大兴趣。非传统的光伏机制，如所谓的体光电效应，在太阳能收集和新的光电子应用方面都是很有前途的候选者。然而，大规模光伏效应的关键方面还没有得到很好的理解。该项目旨在开发一个理论框架来分类和统一晶体固体中的非线性输运，包括块状光伏效应。感兴趣的材料包括二维铁电体和拓扑材料。该框架将确定耗散和载流子相互作用的作用，这些作用尚未在现有的解析或数值理论中解决，但对于理解实验和揭示新的非线性现象非常重要。该项目使用解析场理论方法和数值密度泛函方法。在一个相关的主题中，光也正在成为一种多功能的工具来工程材料的性质，例如最近实现的弗洛奎-布洛赫态和光诱导的反常霍尔效应。这些状态是非常短暂的，因为受辐射的材料很快就会升温。了解热化的途径对于实现新的非平衡态的应用是至关重要的。PI将构建包括电子相互作用、激子和声子在内的多体热化模型，并在这样做的过程中评估激光驱动的非平衡态在现实场景中的机会和挑战。理论模型将通过与进行实验研究的合作伙伴的密切合作进行实验验证。该奖项反映了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 project advances and broadens our basic scientific understanding of materials under intense illumination. Of interest are phenomena and materials where the laws of physics are radically distinct from day-to-day experience due to the smallness of particles inside materials, i.e., quantum physics and quantum materials. Advancing our knowledge of irradiated quantum materials will facilitate their use in future quantum technologies, e.g., more efficient solar energy harvesting, faster computers and optoelectronic applications. This research develops new concepts and methods in both optics and quantum condensed matter physics, benefiting both fields of knowledge. Education and outreach efforts include developing a new computational physics course, hosting a workshop for senior undergraduate students (including those from nearby minority-serving institutions), developing a one-day STEM curriculum unit for low-income high school students enrolled in Upward Bound, hosting middle school teachers via the US State Department’s International Leaders in Education Program, and mentoring undergraduates and graduate students in research. These efforts aim to expand and diversify the STEM workforce.Technical summaryThe need for clean energy sources has led to great interest in solar energy harvesting. Unconventional photovoltaic mechanisms such as the so-called bulk photovoltaic effect are promising candidates for both solar energy harvesting and novel optoelectronic applications. Key aspects of the bulk photovoltaic effect, however, are not well understood. This project aims to develop a theoretical framework to classify and unify nonlinear transport in crystalline solids including the bulk photovoltaic effect. Materials of interest include two-dimensional ferroelectrics and topological materials. The framework will ascertain the role of dissipation and carrier interactions not yet addressed in existing analytical or numerical theories but which are important to understand experiments and uncover novel nonlinear phenomena. The project uses analytical field theoretic methods and numerical density functional approaches.In a related topic, light is also emerging as a versatile tool for engineering the properties of materials as exemplified by the recent realization of the Floquet-Bloch state and the light-induced anomalous Hall effect. These states are very short-lived because irradiated materials quickly heat up. Understanding pathways to thermalization is of fundamental importance in realizing applications of novel nonequilibrium states. The PI will construct models of many-body thermalization which include electron interactions, excitons and phonons and in so doing assess the opportunities and challenges of laser-driven nonequilibrium states in realistic scenarios. Theoretical models will be experimentally validated via close collaboration with partners conducting experimental research.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.