CAREER: Anomalous Quantum Transport - Interactions, Disorder, Topology

该奖项支持理论研究和教育，以促进对介观长度尺度上涉及电子的量子力学效应的理解，介观长度尺度位于原子尺度和我们周围世界的宏观尺度之间。对中尺度电子现象的发现和认识，原则上可以促进新型微型电子器件和技术的发展。对自然界对介结构中电磁、热和光信号传递的基本限制的基本理解，以及定量描述电子之间的相互作用、设计、新材料的相互作用和材料缺陷如何聚集影响或优化电子现象的新兴能力，是未来设备操作和相关技术的基础。该项目旨在通过纳米级电路研究电子传导，其中主导效应需要量子力学来描述，并研究发现的具有许多显着量子力学效应的新材料系统的特性。这些材料包括石墨烯，一类可以导电而不损耗的超导体，以及拓扑材料。拓扑材料包括拓扑绝缘体，它是大部分材料中的绝缘体，但可以在表面或边缘导电，还有Weyl半金属，它的电子看起来是无质量的，并且具有“手性”，这是由它们相对于电子的内在磁性方向的运动方向产生的。PI还将研究可以从普通超导体和半导体材料中设计的拓扑材料。工程拓扑材料可以实现拓扑量子计算。PI将通过多方面的科学推广计划吸引公众和高中生观众，包括指导高中生参加科学奥林匹克校际比赛，组织威斯康星科学体验，公众可以在一个开放的日子里了解物理系的研究和教学。物理博览会将包括实验室参观、动手演示、儿童和家庭活动以及与科学家的非正式对话。该奖项支持理论研究和教育，以促进对介观系统中量子相干性和电子相互作用的相互作用的理解，这是凝聚态物理学核心的一个基本问题。毫无疑问，当今最重要的概念与拓扑对称性、秩序和强相关电子的涌现量子态有关。该项目的中心目标是研究相互作用、无序和带拓扑的相互作用如何在新型多带材料和多层异质结构的异常量子输运中表现出来。该项目的第一个研究目标是建立现代纳米电子器件中电荷、自旋和能量输运的流体动力学理论。该项目的第二个重点是发展非常规超导体的光学响应理论，以及Weyl半金属和二维过渡金属二硫化物的光电现象。第三个工作领域是致力于揭示拓扑绝缘体和超导体量子电路中异常约瑟夫森效应和邻近效应的特性。最终目标是发展具有竞争阶的超导态的非平衡理论，并扩展Keldysh场论方法来描述非常规类别的拓扑绝缘体和超导体。所提出的工作将促进我们对一类拓扑非平凡导体、Weyl半金属、超导体和基于它们的混合纳米系统中电子传输的理解。最近在石墨烯上的实验激发了对流体动力输运的研究，并可能对石墨烯器件的应用有用。对相关材料中竞争相的研究以及对它们的调节和控制的新方法的发现可能会对新的超导体技术的发展产生影响。除了基本兴趣和重要性之外，致力于物质拓扑状态的研究可能对实现新型量子计算能力具有变革性意义。这项研究将通过广泛的公共科学参与计划和推广活动，包括为高中生举办的校际科学奥林匹克竞赛，对理科生和公众观众产生广泛的影响。

NONTECHNICAL SUMMARYThis award supports theoretical research and education to advance understanding of quantum mechanical effects involving electrons on mesoscopic length scales which lie between the scale of an atom and the macroscopic scales of the world around us. The discovery and understanding of electronic phenomena on the mesoscale can in principle lead to the development of novel miniature electronic devices and technologies. Fundamental understanding of the fundamental limits set by nature on the transfer of electromagnetic, thermal and optical signals in mesostructures, together with the emerging capability to quantitatively describe how interactions among electrons, design, interplay of novel materials, and material imperfections converge to affect or optimize electronic phenomena are foundational to future device operation and associated technologies. This project aims to investigate electronic conduction through nanoscale circuits where dominant effects require quantum mechanics for their description, and to study properties of novel materials systems discovered that display many remarkable quantum mechanical effects. These materials include graphene, classes of superconductors which can conduct electricity without loss, and topological materials. Topological materials include topological insulators which are insulators in the bulk of the material but can conduct electricity on the surfaces or edges, and Weyl semimetals which have electrons that appear to be massless and have a "handedness" derived from the direction of their motion relative to the direction of intrinsic magnetism of the electron. The PI will also investigate topological materials that can be engineered from ordinary superconductor and semiconductor materials. Engineered topological materials may enable the realization of topological quantum computing. The PI will engage public and high-school student audiences through a multifaceted outreach science program that includes coaching high-school students for Science Olympiad interscholastic competitions, and organizing Wisconsin Science Experience, an open house in which the public can come to learn about the research and teaching at the Physics Department. The Physics Fair will include laboratory tours, hands-on demonstrations, activities for kids and families, and informal conversations with scientists.TECHNICAL SUMMARY This award supports theoretical research and education to advance understanding of the interplay of quantum coherence and electron interactions in mesoscopic systems, a fundamental problem at the heart of condensed matter physics. Decisively the most important concepts of the present day are related to topological symmetries, orders and emergent quantum states of strongly correlated electrons. The central goal of this project is to investigate how the interplay of interactions, disorder and band topology manifest in anomalous quantum transport specific to novel multiband materials and multilayered heterostructures. The first research objective of this project is to develop a hydrodynamic theory of charge, spin and energy transport in modern nanoelectronic devices. The second thrust of the project is to develop theory of optical response in unconventional superconductors, and photogalvanic phenomena in Weyl semimetals and two-dimensional transition metal dichalcogenides. The third area of work is devoted to revealing peculiarities of anomalous Josephson and proximity effects in quantum circuits of topological insulators and superconductors. The final objective is to develop a nonequilibrium theory of superconducting states with competing orders and extend Keldysh field theoretic approach to describe unconventional classes of topological insulators and superconductors. The proposed work will advance our understanding of electron transport in an actively studied class of topologically nontrivial conductors, Weyl semimetals, superconductors and hybrid nanosystems based upon them. The work on hydrodynamic transport is motivated by recent experiments in graphene, and may be useful to graphene device applications. The research on competing phases in correlated materials and the discovery of novel ways of tuning and controlling them may be impactful for the development of new superconductor based technologies. Apart from the fundamental interest and importance, research devoted to topological states of matter may have transformative implications for the realization of novel quantum computation capabilities. The research will have a broad impact on science students, and public audience through an extensive public science engagement program and outreach activities that include a interscholastic Science Olympiad for high-school students.