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

受限几何中超导体和超流体 3He 中的激发、拓扑缺陷和量子输运

• 批准号: 1106315
• 负责人: James Sauls
• 金额: $ 44万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-11-01 至 2015-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1106315&HistoricalAwards=false
• 关键词: Excitations; Topological; Defects; Quantum; Transport

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.

技术总结该奖项支持理论凝聚态物理学的研究和教育，以预测和发现量子液体、随机固体、超导体和非均质电子和磁性材料中的物理性质，特别是非平衡现象。这项研究在一定程度上回应了最近对凝聚态物质新相的发现和预测，其中包括拓扑凝聚态物质，其中拓扑和对称性在决定其物理性质方面发挥着核心作用。该奖项将进行的具体研究包括基于质量、自旋和电荷传输的定量签名的开发，超导体和量子流体中拓扑激发的声学和光学光谱。与此密切相关的研究包括超流氦-3超导体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。一个关键的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。本研究的另一条主线是对拓扑超导体和超流体中的涡旋和磁畴壁以及耗散机制的研究。这一主题对于理解“拓扑保护”概念在凝聚态中的局限性是很重要的。最后，PI将使用理论模型和统计方法来分析与对称破缺相变、量子流体和固体中的输运相关的有序性与几乎所有宏观物质形式中存在的外在无序之间的相互作用。所提出的理论发展与注入被称为气凝胶的超低密度二氧化硅玻璃中的氦-3的量子液体相的实验研究相联系。这些研究对我们对凝聚态物质的基本理解很重要，并为转化应用提供了希望。量子凝聚相、拓扑凝聚态、新型电子超导体和异质超导和磁性材料具有用于量子信息和计算的下一代电子器件的潜力。这项研究具有强大的教育成分，涉及研究生的培养，延续了PI在尖端研究项目中招收本科生的历史和承诺。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，专注于拟议的研究，这将丰富美国物理科学的研究事业。该奖项支持理论凝聚态物理的研究和教育，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物理性质，在超流和超导体中，以及在能够支持所谓的“拓扑相”的各种电子和磁性材料中。超流是物质的一种状态，在这种状态下，物质的行为就像没有任何粘性的液体，并在整个过程中保持相同的温度。在低温下，超导体具有这样的特性，即电流可以在没有任何阻力的情况下通过它们。拓扑相是一种具有奇异性质的新物质状态，它展示了一种非常微妙的电子内部组织类型，被认为是构建新一代容错计算机的关键，这种计算机使用量子力学在某些任务上远远超过当今最快的计算机。这类材料的性质受量子物理定律和基于对称性和拓扑学的数学原理的支配，对称性和拓扑学是数学的一个主要领域，研究对象在连续变形下保留的空间属性。这项研究涉及最近的实验发现，确定了限制在较小空间区域内的液氦新量子相的存在，例如比人类头发小100倍的空腔、液滴或超薄通道和薄膜、电学性质与磁性共存的超导材料，以及由超导体、磁体和所谓的“拓扑绝缘体”组成的混合材料，这些材料内部不能导电，但允许边缘或边界上的电荷运动。这项研究主要集中在受限几何结构上，因为预计这些材料的表面和界面上会出现新的物理性质。通过基础研究预测和发现的凝聚态物质的许多性质已经产生了应用和新技术，从用于医学诊断的仪器到用于信息存储和高速计算的电子和磁性设备，已经改变了我们的社会。受限几何中的拓扑凝聚物质、新的电子材料以及非均匀超导和磁性材料具有用于量子信息和计算的下一代电子设备的潜力。研究计划具有强大的教育组成部分，涉及研究生的培训，并延续了PI在尖端研究项目中招收本科生的历史和承诺。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，专注于拟议的研究，这将丰富美国物理科学的研究企业。