Order, Topology and Transport in Quantum Matter

量子物质的秩序、拓扑和输运

• 批准号: 1206728
• 负责人: Ashvin Vishwanath
• 金额: $ 32万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206728&HistoricalAwards=false
• 关键词: Order; Topology; Transport; Quantum; Matter

Technical SummaryThis award supports theoretical research and education on quantum condensed matter. It seeks to deepen our understanding of novel quantum states of matter that emerge in many body systems, and to identify experimental signatures and realizations in solids and ultracold quantum gases. While the Landau paradigm of condensed matter accounts for conventional metals and broken symmetry states, here the focus is largely on phases that lie beyond this framework. For example, topological insulators and Weyl semi-metals are phases that admit a description in terms of non-interacting particles, but they possess certain characteristic topological properties. Transport of charge, energy and momentum in the presence of external perturbations are expected to reveal fundamental properties of such phases. These and the interplay with conventional orders, in particular topological defects such as vortices and domain walls, are proposed for study in the first part of this project. The second part of this project addresses strongly correlated topological phases. Promising experimental regimes to realize them, such as flat bands of frustrated lattices and frustrated quantum magnets, will be investigated. Theoretical studies on analogues of fractional quantum Hall states, as well as generalizations to three dimensions are also proposed. Pinpointing the subtle correlations that characterize such states requires new probes, in particular those that can measure non-local properties. Proposing and evaluating such approaches will form the third focus area of this project.This award also supports the education of a graduate student and a postdoctoral research associate at the frontiers of modern theoretical condensed matter physics. The PI will develop a new graduate-level course that cuts across traditional disciplines and integrates the methods and results from the research above. The results will also be disseminated via public lectures and non-technical summaries posted on a public website. From a technological perspective, the novel properties of the quantum states of matter to be investigated in this project can potentially lead to discovery of new materials with useful functionalities and future applications.NonTechnical SummaryThis award supports theoretical research and education on novel states of condensed matter systems. Although quantum mechanical laws govern the microscopic building blocks of matter, the properties observed on a macroscopic scale are often classical; the magnetization of an iron-based magnet being one well-known example. More recently, however, attention has been focused on states of matter which are intrinsically quantum mechanical even at the macroscopic scale, such as "quantum Hall states" as well as "quantum spin liquids" which are actively being sought for in magnetic materials. A key feature of these novel phases is a long range entanglement that is a unique feature intrinsic to quantum mechanical behavior. In this project, the PI and his group will seek to deepen our understanding of such states of matter in order to determine promising arenas for their realization and to propose experimental tests that would signal their presence. It is hoped that these advances in our understanding will eventually lead to a better control over these novel states. This award also supports the education of a graduate student and a postdoctoral research associate at the frontiers of modern theoretical condensed matter physics. The PI will develop a new graduate-level course that cuts across traditional disciplines and integrates the methods and results from the research above. The results will also be disseminated via public lectures and non-technical summaries posted on a public website. From a technological perspective, the novel properties of the quantum states of matter to be investigated in this project can potentially lead to discovery of new materials with useful functionalities and future applications.

技术综述该奖项支持量子凝聚态的理论研究和教育。它试图加深我们对出现在许多身体系统中的物质的新量子态的理解，并识别固体和超冷量子气体中的实验签名和实现。虽然凝聚态的朗道范式解释了传统的金属和破缺的对称态，但这里的重点主要是位于这个框架之外的相。例如，拓扑绝缘体和Weyl半金属是允许用不相互作用的粒子来描述的相，但它们具有某些特征的拓扑性质。在存在外部扰动的情况下，电荷、能量和动量的输运有望揭示这些相的基本性质。这些以及与常规有序的相互作用，特别是拓扑缺陷，如涡旋和磁畴壁，被提出在本项目的第一部分中进行研究。本项目的第二部分涉及强相关的拓扑阶段。实现它们的有希望的实验机制将被研究，例如受挫晶格的平带和受挫量子磁体。还提出了分数量子霍尔态的类比的理论研究，以及对三维的推广。准确地确定这种状态的微妙关联需要新的探测器，特别是那些可以测量非局部性质的探测器。该奖项还支持现代理论凝聚态物理学前沿领域的研究生和博士后研究助理的教育。PI将开发一门新的研究生课程，跨越传统学科，整合上述研究的方法和成果。结果还将通过公共讲座和在公共网站上张贴的非技术性摘要来传播。从技术的角度来看，这个项目要研究的物质量子态的新性质可能会导致发现具有有用功能和未来应用的新材料。非技术概述该奖项支持关于凝聚态系统新态的理论研究和教育。尽管量子力学定律支配着物质的微观构件，但在宏观尺度上观察到的性质往往是经典的；铁基磁体的磁化就是一个众所周知的例子。然而，最近人们的注意力集中在即使在宏观尺度上也是量子力学的物质状态上，例如正在磁性材料中积极寻找的“量子霍尔态”以及“量子自旋液体”。这些新相的一个关键特征是长程纠缠，这是量子力学行为固有的一个独特特征。在这个项目中，PI和他的团队将寻求加深我们对这种物质状态的理解，以便确定它们实现的有希望的领域，并提出表明它们存在的实验测试。人们希望，我们在理解上的这些进步最终将导致对这些新状态的更好控制。该奖项还支持现代理论凝聚态物理前沿的研究生和博士后研究助理的教育。PI将开发一门新的研究生课程，跨越传统学科，整合上述研究的方法和成果。结果还将通过公共讲座和在公共网站上张贴的非技术性摘要来传播。从技术角度来看，该项目要研究的物质量子态的新颖性质可能会导致发现具有有用功能和未来应用的新材料。