CAREER: Theoretical and Numerical Investigation of Symmetric Mass Generation

职业：对称质量生成的理论和数值研究

基本信息

批准号：
2238360
负责人：
Yi-Zhuang You
金额：
$ 57.5万
依托单位：
University of California-San Diego
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：
2023-01-15 至 2027-12-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2238360&HistoricalAwards=false
关键词：
CAREER Theoretical Numerical Investigation Symmetric

项目摘要

NONTECHNICAL SUMMARYThis CAREER award supports research and educational activities to explore novel quantum mechanisms that transform metals into insulators by increasing the interaction strength between electrons in such materials. In solid-state physics, the electronic structure theory provides the standard description for metals and insulators, such that the highest-energy electrons lie within an energy band for metals or in the band gap, a forbidden zone, as is the case for insulators. In this theory, transforming material from metal to insulator corresponds to a band gap opening in the electron energy spectrum, which always requires a change in the symmetry properties of the material to modify its band structure. This research aims to study a different mechanism for the metal-to-insulator transformation that is beyond the standard electronic structure theory in which the interaction and subsequent correlated motion of the electrons play the central role. The novel mechanism is called symmetric mass generation, which opens an excitation gap in the electron many-body energy spectrum without any change of symmetry properties — a phenomenon that is not explained by standard electronic structure theory. Understanding this novel mechanism may have implications in classifying quantum phases of matter in condensed matter physics and understanding the origin of mass for fundamental matter particles in high-energy physics. This project will investigate symmetric mass generation with an aim to address: (1) how appropriate interactions can be designed to realize this phenomenon, (2) what happens precisely as the metal becomes an insulator, (3) what are the unique experimental signatures of the novel insulator that distinguish it from conventional band insulators. The educational activity focuses on retaining LGBT+ (lesbian, gay, bisexual, transgender, and other gender and sexual minorities) students in physics by providing them with research opportunities and increasing LGBT+ visibility on campus. The effort will build a more diverse and inclusive academic environment that attracts talented under served students to physics and contribute to developing a diverse and globally competitive workforce in science.TECHNICAL SUMMARYThis CAREER award supports research and educational activities to study a novel mechanism for the gap opening (mass generation) of fermions in interacting quantum many-body systems, called the symmetric mass generation. The mechanism is a non-perturbative interaction-driven gap-opening effect that cannot be interpreted as a change in the single-particle band structure. Symmetric mass generation provides a new mechanism for metal-insulator transition beyond current band theory in condensed matter physics and a new origin for fermion mass beyond the standard Higgs mechanism. This research can advance the understanding of interacting topological insulators and transform the frontier knowledge about mass generation. The research will explore three related aspects: (1) the principle of designing appropriate interaction to realize the symmetric mass generation insulating phase, (2) the universal properties of the gap-opening transition under the symmetric mass generation interaction, and (3) the effect of doping symmetric mass generation insulators and the possibility to realize symmetric mass generation on the Fermi surface in a Fermi liquid. The research will combine field theory, for example, categorical symmetry, duality, monopole scaling, and dimension reduction, and numerical simulation, for example machine-learning-assisted variational Monte Carlo methods, to tackle scientific problems about symmetric mass generation. The research outcome will advance the knowledge frontier of interacting topological phases, strongly correlated materials, and lattice regularization for chiral fermions. The educational activities will focus on supporting and retaining LGBT+ (lesbian, gay, bisexual, transgender, and other gender and sexual minorities) undergraduates in physics and building a welcoming local community for LGBT+ students/researchers at all levels. These objectives will be attained by (1) providing mentored research opportunities to the targeted group and (2) initiating and organizing a weekly tea-time social event for LGBT+ students/researchers in Physics Department at UCSD.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.

非技术摘要该职业奖支持研究和教育活动，以探索通过增加材料中电子之间的相互作用强度将金属转变为绝缘体的新型量子机制。在固态物理学中，电子结构理论为金属和绝缘体等提供了标准描述。最高能量的电子位于金属的能带内或带隙（禁带）内，就像绝缘体的情况一样，将材料从金属转变为绝缘体。对应于电子能谱中的带隙开口，这总是需要改变材料的对称性来改变其能带结构。本研究旨在研究超越金属到绝缘体转变的不同机制。标准电子结构理论，其中电子的相互作用和随后的相关运动起着核心作用，这种新机制被称为对称质量生成，它在电子多体能谱中打开了一个激发间隙，而对称性没有任何变化——标准电子结构理论无法解释的现象。理解这种新颖的机制可能会对凝聚态物理学中物质的量子相进行分类以及理解高能物理学中基本物质粒子的质量起源产生影响。该项目将研究对称质量的生成，旨在解决：（1）如何产生。可以设计适当的相互作用来实现这种现象，（2）当金属变成绝缘体时会发生什么，（3）新型绝缘体与传统带状绝缘体的独特实验特征是什么？教育活动的重点是保留。同性恋者+通过为物理专业的学生（女同性恋、男同性恋、双性恋、跨性别者以及其他性别和性少数群体）提供研究机会并提高 LGBT+ 在校园的知名度，这一努力将建立一个更加多元化和包容性的学术环境，吸引有才华且服务不足的学生。物理学，并为科学领域多样化和具有全球竞争力的劳动力做出贡献。技术摘要该职业奖支持研究和教育活动，以研究在相互作用的量子开发多体系统中费米子间隙打开（质量生成）的新机制，称为对称该机制是一种非微扰相互作用驱动的间隙打开效应，不能解释为单粒子能带结构的变化。对称质量生成为凝聚态中的当前能带理论提供了一种新的金属-绝缘体转变机制。该研究将探索三个相关方面：（1）设计原理。实现对称质量产生绝缘相的适当相互作用，（2）对称质量产生相互作用下开隙转变的普遍性质，以及（3）掺杂对称质量产生绝缘体的效果和实现对称质量产生的可能性该研究将结合场论（例如分类对称性、对偶性、单极尺度和降维）和数值模拟（例如机器学习辅助的变分蒙特卡罗）。研究成果将推进强相互作用拓扑相、相关材料和手性费米子晶格正则化的知识前沿。教育活动将侧重于支持和保留 LGBT+（女同性恋、男同性恋、双性恋、跨性别者以及其他性别和性少数群体）物理学本科生，并为各级 LGBT+ 学生/研究人员建立一个热情的当地社区。这些目标将通过以下方式实现：(1) 向学生提供指导性研究机会。目标群体；(2) 发起和组织每周一次的下午茶时间社交活动，反映加州大学圣地亚哥分校物理系的 LGBT+ 学生/研究人员的情况。该奖项符合 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响进行评估，被认为值得支持审查标准。