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.

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，超导体和异质电子和磁性材料中的物理性质，特别是非平衡现象。这项研究部分回应了最近对凝聚态新阶段的发现和预测，包括“拓扑凝聚态”，其中拓扑和对称性在确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超导体和量子流体中拓扑激发的质量，自旋和电荷传输，声学和光学光谱的定量签名的开发。 密切相关的研究包括集体表面激发和超流氦三和手性自旋三重态超导体，如Sr 2 RuO 4和UPt 3，在薄膜，导电通道和点接触的非平衡特性的理论研究。一个关键的目标是预测和量化的签名的表面状态和它们的输运性质的拓扑超导体和超流体。 本研究的另一个线索是研究拓扑超导体和超流体中的涡旋和畴壁以及耗散机制。这一主题对于理解凝聚态物质中“拓扑保护”概念的局限性具有重要意义。 最后，PI将采用理论模型和统计方法来分析与对称性破缺相变相关的有序性，量子流体和固体中的传输以及几乎所有宏观形式物质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超低密度二氧化硅玻璃（称为气凝胶）的氦-3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很重要，并有望在转化应用中发挥作用。量子凝聚相、拓扑凝聚物质、新型电子超导体以及异质超导和磁性材料都有可能成为下一代量子信息和计算的电子器件。该研究具有很强的教育成分，涉及研究生的培养，并延续了PI在尖端研究项目中招募本科生的历史和承诺。该研究涉及与英国，法国和日本的研究团队进行的大量国际合作，专注于拟议的研究，这将丰富美国物理科学的研究事业。非技术摘要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物理性质，在超流体和超导体中，以及在可以支持所谓的“拓扑相”的各种电子和磁性材料中。超流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性的流体，并且在整个过程中保持相同的温度。在低温下，超导体具有电可以在没有任何阻力的情况下流过它们的特性。拓扑相，具有奇异性质的新物质状态，表现出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，这些计算机采用量子力学，在某些任务上大大超过当今最快的计算机。这种材料的性质受量子物理定律和基于对称性和拓扑学的组织数学原理的支配，这是数学的一个主要领域，涉及物体连续变形下保持的空间性质。这项研究涉及最近的实验发现，这些发现证实了空间小区域中存在新的液氦量子相，例如比人类头发小100倍的空腔，液滴或超薄通道和薄膜，电性能与磁性能共存的超导材料，以及由超导体组成的混合材料，磁体和所谓的“拓扑绝缘体”，它们不能在内部导电，但允许电荷在它们的边缘或边界上移动。该研究的重点是受限的几何形状，因为新的物理性质预计会发生在这些材料的表面和界面。凝聚态物质的许多性质已经被预测和发现，作为基础研究的结果，已经导致了应用和新技术，从医疗诊断仪器到信息存储和高速计算的电子和磁性设备，这些都改变了我们的社会。在有限的几何拓扑凝聚态物质，新的电子材料和异质超导和磁性材料有潜力的下一代电子设备的量子信息和计算。该研究计划有一个强大的教育组成部分，涉及研究生的培训和PI的历史和承诺的延续，在尖端的研究项目招募本科生。该研究涉及与英国，法国和日本的研究团队进行的大量国际合作，重点是拟议的研究，这将丰富美国物理科学的研究事业。