NSF-BSF: Theory of Quantum Materials

NSF-BSF：量子材料理论

• 批准号: 2310312
• 负责人: Steven Kivelson
• 金额: $ 65万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310312&HistoricalAwards=false
• 关键词: NSF; BSF; Theory; Quantum; Materials

NONTECHNICAL SUMMARYThis award supports theoretical research on atomic scale models of interacting electrons and ions in so-called "quantum materials". Some examples of quantum materials include high-temperature superconductors, two layers of carbon atom sheets on top of each other with a relative twist angle, and materials in which the electron-electron interaction energies are comparable or much larger compared to their kinetic energies. A major focus of this project is to unravel the mysterious properties of superconductors through which electrons flow in unison without losing any of their energy below a certain critical temperature. While quantum mechanics has allowed scientists to understand and predict most properties of "conventional" superconductors, achieving a fundamental understanding of unconventional superconductors, which include high-temperature superconductors and twisted layers of carbon atoms, has remained elusive. In this project, the PI and his team will study an array of atomic scale models on material systems and topics, including unconventional superconductors, that are at the heart of contemporary condensed matter physics.The quantum many-body problem that is the topic of this project has diverse and deep connections to other fields of physics, from string theory to quantum information. In addition, quantum materials have had a tremendous impact on both fundamental science and technology, and hence, an increased understanding of the problems to be investigated in this project has the potential to influence broader developments in science and technology. This award will also contribute to the development of the scientific workforce, as it will support the research training of graduate students and postdocs, who are likely to take leading positions in academia and industry in the future.TECHNICAL SUMMARYThis award supports theoretical research on microscopic models of interacting electrons and phonons in quantum materials. Particular attention will be paid to the intermediate coupling regime, where interactions and kinetic terms are of comparable magnitude. Interactions are generally minimized when the constituent particles form suitable real-space structures, such as a Wigner crystal, while kinetic terms are diagonal in momentum space. Hence, the intermediate coupling regime is where quantum frustration is maximal. The PI will also apply a Landau-Ginzburg-Wilson effective field theoretical approach to study problems in which multiple distinct ordering tendencies are present, and the effective frustration reflects the competition between them. Specific problems of this general sort that will be the focus of study are (i) Solvable models of unconventional metallic regimes, particularly focusing on lessons for cuprate superconductors, (ii) Phenomenological and microscopic theories of systems with multiple intertwined ordering tendencies, including multiple possible uniform superconducting orders, pair-density-wave order, charge and spin density wave order, and electron nematic order, (iii) Correlated phases of multi-valley two-dimensional electron gases, and (iv) Generalizing the classification of distinct phases, especially unconventional superconducting phases, to quasi-periodic systems including Moiré materials in which Bloch's theorem does not apply and conventional symmetry classifications at the very least must be reconsidered.The quantum many-body problem that is the topic of this project has diverse and deep connections to other fields of physics, from string theory to quantum information. In addition, quantum materials have had a tremendous impact on both fundamental science and technology, and hence, an increased understanding of the problems to be investigated in this project has the potential to influence broader developments in science and technology. This award will also contribute to the development of the scientific workforce, as it will support the research training of graduate students and postdocs, who are likely to take leading positions in academia and industry in the future.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要该奖项支持对所谓“量子材料”中电子和离子相互作用的原子尺度模型的理论研究。量子材料的一些例子包括高温超导体、彼此相对扭曲的两层碳原子片。该项目的一个主要重点是揭示电子流过的超导体的神秘特性。量子力学使科学家能够理解和预测“传统”超导体的大多数特性，从而对非常规超导体（包括高温超导体和扭曲层）有一个基本的了解。碳原子仍然难以捉摸，在这个项目中，首席研究员和他的团队将研究一系列关于材料系统和主题的原子尺度模型，包括处于当代核心地位的非常规超导体。该项目的主题是量子多体问题，它与从弦理论到量子信息的其他物理学领域有着广泛而深入的联系。此外，量子材料对基础科学和量子信息都产生了巨大的影响。技术，因此，加深对本项目要研究的问题的了解有可能影响科学和技术的更广泛发展。该奖项也将有助于科学劳动力的发展，因为它将支持研究培训。研究生和博士后，他们可能在以下领域担任领导职务技术摘要该奖项支持量子材料中相互作用的电子和声子的微观模型的理论研究，将特别关注中间耦合机制，其中相互作用和动力学项通常具有可比的量级。当组成粒子形成合适的实空间结构（例如维格纳晶体）时，而动力学项在动量空间中是对角线的，因此，中间耦合状态是量子挫败最大的地方。一种朗道-金茨堡-威尔逊有效场理论方法来研究存在多种不同排序倾向的问题，并且有效挫败反映了它们之间的竞争，这将成为研究的重点：（i）可解决。非常规金属体系的模型，特别关注铜酸盐超导体的经验教训，（ii）具有多种相互交织的有序倾向的系统的现象学和微观理论，包括多种可能的统一超导秩序，对密度波序、电荷和自旋密度波序以及电子向列序，(iii) 多谷二维电子气的相关相，以及 (iv) 概括不同相的分类，特别是非常规超导相，对于包括布洛赫定理不适用的莫尔材料在内的准周期系统，至少必须重新考虑传统的对称性分类。量子多体问题是本文的主题该项目与从弦理论到量子信息的其他物理学领域有着广泛而深入的联系。此外，量子材料对基础科学和技术都产生了巨大的影响，因此，人们对这一领域要研究的问题有了更多的理解。该项目有潜力影响更广泛的科学和技术发展，该奖项还将有助于科学劳动力的发展，因为它将支持研究生和博士后的研究培训，他们可能在学术界和工业界占据领先地位。该奖项反映了 NSF 的法定使命和通过使用基金会的智力价值和更广泛的影响审查标准进行评估，该项目被认为值得支持。