Excitations, Topological Defects and Quantum Transport in Superconductors and Superfluid 3He in Confined Geometries

该奖项支持理论凝聚态物理学的研究和教育，以预测和发现物理性质，特别是量子液体，随机固体，超导体和异质电子和磁性材料中的非平衡现象。这项研究在一定程度上回应了最近对凝聚态新相的发现和预测，包括“拓扑凝聚态”，其中拓扑和对称性在决定其物理性质方面都起着核心作用。该奖项将进行的具体研究包括基于质量、自旋和电荷输运、超导体和量子流体中拓扑激发的声学和光学光谱的定量特征的发展。密切相关的研究包括超流体氦- 3和手性自旋三重态超导体（如Sr2RuO4和UPt3）在薄膜、导电通道和点接触中的集体表面激发和非平衡性质的理论研究。一个关键目标是预测和量化拓扑超导体和超流体的表面态及其输运性质的特征。本研究的另一个方向是研究涡旋和畴壁，以及拓扑超导体和超流体中的耗散机制。这个主题对于理解凝聚态物质中“拓扑保护”概念的限制是很重要的。最后，PI将采用理论模型和统计方法来分析与对称破缺相变相关的有序、量子流体和固体中的输运以及存在于几乎所有物质宏观形式中的外在无序之间的相互作用。提出的理论发展与氦- 3注入超低密度二氧化硅玻璃（称为气凝胶）的量子液相的实验研究有关。这些研究对我们对凝聚态物质的基本理解是重要的，并有望转化应用。量子凝聚相、拓扑凝聚态物质、新型电子超导体和非均质超导磁性材料具有下一代量子信息和计算电子器件的潜力。这项研究有很强的教育成分，包括研究生的培训，以及PI在招募本科生参与尖端研究项目方面的历史和承诺的延续。这项研究涉及与英国、法国和日本的研究团队进行大量的国际合作，重点研究拟议的研究，这将丰富美国的物理科学研究事业。该奖项支持理论凝聚态物理学的研究和教育，以预测和发现物理性质，特别是那些在远离平衡的情况下实现的，在超流体和超导体中，以及在各种电子和磁性材料中，可以支持所谓的“拓扑相”。超流动性是物质的一种状态，在这种状态下，物质的行为就像没有任何粘度的流体，并保持相同的温度。在低温下，超导体具有电流可以毫无阻力地通过的特性。拓扑相是具有奇异性质的物质的新状态，展示了一种非常微妙的电子内部组织，被认为是构建新一代容错计算机的关键，这种计算机利用量子力学在某些任务上大大超过当今最快的计算机。这些材料的性质受量子物理定律和基于对称和拓扑的组织数学原理的支配，这是数学的一个主要领域，处理在物体连续变形下保持的空间性质。这项研究与最近的实验发现有关，这些发现证实了液氦在空间小区域内存在新的量子相，例如比人类头发小100倍的空腔，液滴或超薄通道和薄膜，电性能与磁性共存的超导材料，以及由超导体组成的混合材料。磁铁和所谓的“拓扑绝缘体”不能在其内部导电，但允许电荷在其边缘或边界上移动。研究的重点是受限几何，因为新的物理性质预计会出现在这些材料的表面和界面上。作为基础研究的结果，凝聚态物质的许多特性已经被预测和发现，并带来了应用和新技术，从医疗诊断仪器到用于信息存储和高速计算的电子和磁性设备，这些设备已经改变了我们的社会。受限几何拓扑凝聚态物质、新型电子材料和非均质超导磁性材料具有下一代量子信息和计算电子器件的潜力。该研究项目有很强的教育成分，包括研究生的培训和PI的历史的延续，以及在前沿研究项目中招募本科生的承诺。这项研究涉及与英国、法国和日本的研究团队进行大量的国际合作，重点研究拟议的研究，这将丰富美国的物理科学研究事业。

TECHNICAL SUMMARYThis award supports research and education in theoretical condensed matter physics for the prediction and discovery of physical properties, particularly non-equilibrium phenomena, in quantum liquids, random solids, superconductors, and heterogeneous electronic and magnetic materials. This research responds in part to recent discoveries and predictions of new phases of condensed matter, including "topological condensed matter", in which the both topology and symmetry play central roles in determining their physical properties. Specific studies that will be pursued with this award include the development of quantitative signatures based on mass, spin and charge transport, acoustic and optical spectroscopy of topological excitations in superconductors and quantum fluids. Closely related research includes theoretical investigations of collective surface excitations and non-equilibrium properties of superfluid helium-three and chiral spin-triplet superconductors, e.g. Sr2RuO4 and UPt3, in thin films, conducting channels, and point contacts. A key goal is to predict and quantify signatures of surface states and their transport properties for topological superconductors and superfluids. Another thread in this research is the investigation of vortices and domain walls, and mechanisms of dissipation in topological superconductors and superfluids. This topic is important for understanding limits of the concept of "topological protection" in condensed matter. Finally, the PI will employ theoretical models and statistical methods for analyzing the interplay between ordering associated with symmetry breaking phase transitions, transport in quantum fluids and solids and extrinsic disorder that is present in virtually all macroscopic forms of matter. The proposed theoretical developments connect with experimental studies of the quantum liquid phases of helium-three infused into ultra-low density silica glass, called aerogel. These studies are important to our basic understanding of condensed matter, and hold promise for transformational applications. Quantum condensed phases, topological condensed matter, novel electronic superconductors and heterogeneous superconducting and magnetic materials have potential for next-generation electronic devices for quantum information and computation.The research has a strong education component involving the training of graduate students and a continuation of the PI's history and commitment in recruiting undergraduates in cutting edge research projects. The research involves substantial international collaboration with research teams in the United Kingdom, France and Japan focused on the proposed research, which will enrich the research enterprise in the physical sciences in the US.NON-TECHNICAL SUMMARYThis award supports research and education in theoretical condensed matter physics for the prediction and discovery of physical properties, particularly those that are realized in situations far from equilibrium, in superfluids and superconductors, and in various electronic and magnetic materials that can support so-called "topological phases". Superfluidity is a state of matter in which the matter behaves like a fluid without any viscosity and maintains the same temperature throughout itself. At low temperatures, superconductors have the property that electricity can flow through them without any resistance. Topological phases, new states of matter with exotic properties, exhibit a very subtle type of internal organization of electrons, and are believed to hold the key to building a new generation of fault-tolerant computers that employ quantum mechanics to drastically outperform today's fastest computers for certain tasks. The properties of such materials are governed by the laws of quantum physics and organizing mathematical principles based on symmetry and topology, which is a major area of mathematics that deals with spatial properties preserved under continuous deformations of objects. The research relates to recent experimental discoveries establishing the existence of new quantum phases of liquid helium confined in small regions of space, such as cavities that are some 100 times smaller than the human hair, droplets or ultra-thin channels and films, superconducting materials whose electrical properties co-exist with magnetic properties, and hybrid materials composed of superconductors, magnets and the so-called "topological insulators" that cannot conduct electricity in their interior but allow movement of charges on their edges or boundaries. The research focuses on confined geometries because new physical properties are predicted to occur on surfaces and interfaces of these materials. Many properties of condensed matter that have been predicted and discovered as a result of basic research have resulted in applications and new technologies, from instrumentation for medial diagnostics to electronic and magnetic devices for information storage and high-speed computation that have transformed our society. Topological condensed matter in confined geometries, new electronic materials and heterogeneous superconducting and magnetic materials have potential for next-generation electronic devices for quantum information and computation.The research program has a strong education component involving the training of graduate students and a continuation of the PI's history and commitment in recruiting undergraduates in cutting edge research projects. The research involves substantial international collaboration with research teams in the United Kingdom, France and Japan focused on the proposed research, which will enrich the research enterprise in the physical sciences in the US.