Strong Electron Correlations and Quantum Critical Phenomena

强电子相关性和量子临界现象

• 批准号: 0605769
• 负责人: Philip Phillips
• 金额: $ 44万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605769&HistoricalAwards=false
• 关键词: Strong; Electron; Correlations; Quantum; Critical

This award supports theoretical research and education in condensed matter physics with a focus on aspects of strongly correlated electron phenomena. Three key ideas lie at the heart of this project: 1) spectral weight transfer across the Mott gap suggests that the correct low-energy theory of doped Mott insulators involves a charge 2e bosonic field, 2) the suppression of the Josephson effect in nanowires below a critical diameter originates from the onset of a superconducting state with a pairing symmetry that is orthogonal to the s-wave state in the leads, and 3) the origin of the metallic state in thin metal film alloys displaying a putative insulator-superconductor transition is driven by glassiness. The goal of this project is to confirm and elucidate each of these ideas. This project focuses on developing theoretical tools and new ideas to elucidate key experimental systems that are dominated by large Coulomb repulsions or systems near quantum critical points. Of course in the presence of disorder, new phases are possible, such as glasses. Precisely how metallic phases obtain in two dimensions for either bosons or fermions is not known. This project continues to develop a possible resolution of this problem, as well as a systematic way of approaching many aspects of the strongly correlated problem. Broader Impact: This award supports graduate students seeking their PhD degrees in theoretical solid state physics. As the large Coulomb repulsion and disorder problems are central to solid state physics, it is essential that students gain expertise in this area. In addition to the training of graduate students, several other broad educational goals will be met. First, as a result of the PI's commitment to the communication of the current status of theoretical solid state physics to the next generation of students, he has written a much-needed graduate textbook, "Advanced Solid State Physics." The PI plans a new edition will which will incorporate new material on strongly correlated systems which helps integrate forefront research into an educational text. A new course at Illinois, entitled "Quantum Phase Transitions," has been developed as a direct outgrowth from NSF-funded research. A second important feature of this project is the PI's impact as a highly visible and effective role model for minority students in the Department of Physics and the College of Engineering (COE) at Illinois. A novel outreach component of the project is the PI's involvement in assisting scientists in developing countries. He recently organized an international workshop in Trinidad and Tobago on "Mottness and Quantum Criticality" which helped to introduce scientists from the Caribbean to frontier problems in strongly correlated electron materials. In addition, the PI is the Chair of the organizing committee for the symposium and educational and museum outreach for the 50th anniversary of the publication of the Bardeen-Cooper-Schrieffer theory of superconductivity. NON-TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics. The proposal focuses on the discovery and understanding of new states of matter that occur when the interactions among electrons are very large and lead to strong correlations in their motion. High temperature superconductors are examples of a class of materials in which strong interactions among electrons lead to new states of matter. Among the states of matter that the PI will study are the insulating state that arises as a consequence of strong interactions among electrons, known as a Mott insulator, and new states of matter that may be hidden in a transformation that takes place between superconducting and insulating states observed in thin films. The PI will focus on developing theoretical tools and new ideas to elucidate the underlying physics of key experimental systems and to understand how new metallic states arise.The PI is a highly visible and effective role model for minority students in the Department of Physics and the College of Engineering (COE) at Illinois. This award supports some of his education and outreach activities, including graduate level education in theoretical condensed matter physics with a focus on central problems of the field. The PI's research will contribute to his work to create a new edition of his graduate level textbook, "Advanced Solid State Physics," which will incorporate new material and integrate forefront research into the text. The PI activities in assisting scientists in developing countries to modernize their research constitute an outreach component of this project. His activities as Chair of the organizing committee for the symposium and educational and museum outreach for the 50th anniversary of the publication of the Bardeen-Cooper-Schrieffer theory of superconductivity are another component of his outreach efforts.

该奖项支持凝聚态物理的理论研究和教育，重点放在强关联电子现象的各个方面。这个项目的核心有三个关键概念：1)跨Mott带隙的光谱重量转移表明，掺杂Mott绝缘体的正确低能理论涉及一个电荷2E玻色场；2)在临界直径以下的纳米线中约瑟夫森效应的抑制源于超导态的开始，其对对称性与引线中的S波态垂直；3)金属薄膜合金中金属态的起源是由玻璃性驱动的。这个项目的目标是确认和阐明每一个想法。这个项目致力于开发理论工具和新的想法来阐明主要由大库仑排斥或量子临界点附近的系统主导的关键实验系统。当然，在无序存在的情况下，新的相是可能的，比如玻璃。对于玻色子或费米子来说，金属相在二维中是如何获得的还不得而知。该项目继续制定这一问题的可能解决办法，以及系统地处理这一密切相关问题的许多方面。更广泛的影响：该奖项支持研究生攻读理论固态物理学博士学位。由于大型库仑排斥和无序问题是固态物理的核心，因此学生在这一领域获得专业知识是至关重要的。除了培养研究生，还将实现其他几个广泛的教育目标。首先，由于PI致力于将理论固态物理的现状传达给下一代学生，他编写了一本急需的研究生教科书--《高级固态物理》。PI计划一个新版本的遗嘱，它将纳入关于强相关系统的新材料，这有助于将前沿研究整合到教育文本中。伊利诺伊州大学开设了一门名为“量子相变”的新课程，这门课程是由美国国家科学基金会资助的研究直接衍生出来的。这个项目的第二个重要特点是，作为伊利诺伊州物理系和工程学院(COE)少数族裔学生的高度可见和有效的榜样，PI产生了影响。该项目的一个新的外展部分是国际和平协会参与协助发展中国家的科学家。他最近在特立尼达和多巴哥组织了一次关于“杂色和量子临界性”的国际讲习班，帮助加勒比地区的科学家了解强相关电子材料中的前沿问题。此外，国际超导学会是巴丁-库珀-施里弗超导理论发表50周年研讨会、教育和博物馆宣传活动的组织委员会主席。非技术综述：该奖项支持凝聚态物理的理论研究和教育。该提议的重点是发现和理解当电子之间的相互作用非常大并导致它们运动中的强关联时发生的新的物质状态。高温超导体是一类材料的例子，在这种材料中，电子之间的强烈相互作用导致物质的新状态。PI将研究的物质状态包括被称为Mott绝缘体的电子之间强烈相互作用产生的绝缘态，以及在薄膜中观察到的超导和绝缘态之间发生的转变中可能隐藏的新物质状态。PI将专注于开发理论工具和新想法，以阐明关键实验系统的基本物理原理，并了解新的金属状态是如何出现的。PI是伊利诺伊州物理系和工程学院(COE)少数族裔学生高度可见和有效的榜样。该奖项支持他的一些教育和推广活动，包括研究生水平的理论凝聚态物理教育，重点关注该领域的核心问题。PI的研究将有助于他创建研究生水平教科书的新版本，该教科书将纳入新材料，并将前沿研究整合到文本中。协助发展中国家科学家使其研究现代化的私营部门活动是该项目的一个外展部分。他作为巴丁-库珀-施里弗超导理论发表50周年研讨会组织委员会主席以及教育和博物馆外联活动是他外联工作的另一个组成部分。