CAREER: Theories of Gapless Quantum Matter Beyond Quasiparticles

职业：超越准粒子的无带隙量子物质理论

• 批准号: 2237522
• 负责人: Debanjan Chowdhury
• 金额: $ 60.77万
• 依托单位: Cornell 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: 2023-04-01 至 2028-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237522&HistoricalAwards=false
• 关键词: CAREER; Theories; Gapless; Quantum; Matter

NONTECHNICAL SUMMARYThis CAREER award supports an integrated research, outreach, and education program in theoretical condensed matter physics. At sufficiently low temperature some materials can exhibit superconductivity, a state of matter where electrons self-organize into a cooperative state which can conduct electricity without dissipation. The search for superconductivity at high temperatures is driven by the potential of superconductors to transform the future of quantum technologies and human society, with applications in energy storage and transmission, medical diagnostics, and quantum computing. However, the microscopic reasons for superconductivity at high temperature remain mysterious. The research will be focused on a class of unconventional metals, which are the “parent” states for high temperature superconductors. Unlike simple metals such as copper, whose properties can be effectively understood by considering the electrons one at a time, these unconventional metals are best described as a collective quantum fluid where the electrons are strongly entangled over long distances with one another. This research will develop the required technical framework to describe these entangled electronic liquids. This will pave the way for identifying the key microscopic mechanisms responsible for the origin of superconductivity at high temperatures.The PI and his group will develop new theoretical methods building on recent theoretical developments across different subfields. The PI will develop exact theoretical methods that have a predictive power that can be tested against experiments on real materials in the laboratory. The resulting outcome will impact the fundamental understanding of the collective quantum mechanical properties of trillions of entangled electrons, and potentially help guide the future search for new materials displaying exotic properties. The methods and results will be disseminated to the wider community.In parallel, the PI will initiate and participate in a variety of educational and outreach activities. Although quantum physics has impact on the development of new technologies that become part of everyone’s daily lives, it has a reputation for being inaccessible. The PI will start a new podcast series, which will host informal discussions with a diverse lineup of well-known researchers, to get students and the general public excited about the physics of quantum materials. The PI will also organize workshops for high school science teachers to co-develop engaging lesson plans. The PI will mentor undergraduate and graduate students in original research, and write pedagogical articles aimed at training them in the new scientific developments aligned with the research activities.TECHNICAL SUMMARYThis CAREER award supports an integrated research, outreach, and education program in theoretical condensed matter physics. The goal of the research will be to address some of the key facets of the long-standing mystery of high-temperature superconductivity. Specifically, the focus will be on the unusual gapless metallic phases out of which superconductivity emerges in quantum materials. Experiments suggest that the quantum motion of electrons is frustrated and entangled over long distances in strongly correlated metals, and the microscopic degrees of freedom, namely electrons and phonons, are strongly intertwined with each other. This research activity will develop novel, non-perturbative theoretical approaches to solve the problem of electronic liquids entangled with other collective degrees of freedom, to expose universal aspects of gapless quantum many-body systems.The PI will formulate new approaches for studying interacting gapless phases that do not rely on the existence of well-defined, electron-like (“quasiparticle”) excitations. To address their non-trivial dynamics, the PI will develop novel theoretical techniques that are based on technical advances in the study of frustrated magnets, thermalization in chaotic quantum many-body systems, and numerically exact algorithms that do not suffer from the fermion “sign problem”. The PI will build on the following conjectures: (i) interacting frustrated liquids offer a non-trivial starting point for including the effects of quantum fluctuations and describing previously unexplored gapless phases; and (ii) the conventional theory for electrical transport in metals can break down over a wide range of intermediate temperatures for sufficiently “chaotic” models with generic interactions. The PI will also exploit recent breakthroughs in the highly controllable moiré systems, focusing on the problem of narrow electronic bands coupled to low-energy phonons using numerically exact methods. Analyzing these questions will offer an important conceptual framework for tying together a vast amount of existing experimental data on high-temperature superconductors, and help direct the search for new materials displaying similar phenomena.The PI’s educational and outreach activities are integrated synergistically with the research. The PI will start a new podcast series with a diverse lineup of well-known researchers to increase awareness about the excitement in the field amongst the general public and students. The PI will mentor undergraduate and graduate students in original research, and write pedagogical articles aimed at training them at the new scientific developments aligned with the research activities. Leveraging existing infrastructure available at Cornell University through the STEM teacher program, the PI will organize a series of workshops for high school science teachers to co-develop engaging lesson plans.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理论凝聚态物理学的综合研究、推广和教育计划，一些材料在足够低的温度下可以表现出超导性，这是一种电子自组织成合作状态的物质状态，可以导电而不耗散。超导体改变量子技术和人类社会未来的潜力推动了对高温超导性的研究，其应用领域包括能量存储和传输、医疗诊断和量子技术。然而，高温超导的微观原因仍然是个谜，该研究将集中在一类非常规金属上，它们是高温超导体的“母”态，而铜等简单金属的特性可能是不同的。通过一次考虑一个电子来有效地理解，这些非常规金属最好被描述为一种集体量子流体，其中电子在长距离上彼此强烈纠缠。这项研究将开发描述这些纠缠所需的技术框架。这将为确定高温超导起源的关键微观机制铺平道路。 PI 和他的团队将在不同子领域的最新理论发展的基础上开发新的理论方法。具有预测能力，可以在实验室中对真实材料进行实验进行测试，所得结果将影响对数万亿纠缠电子的集体量子力学特性的基本理解，并可能有助于指导未来寻找具有奇异特征的新材料。属性。同时，PI 将发起并参与各种教育和推广活动，尽管量子物理学对成为每个人日常生活一部分的新技术的发展产生了影响。 PI 将启动一个新系列，与各种知名研究人员进行非正式的播客讨论，以激发学生和公众对量子材料物理学的兴趣。PI 还将组织研讨会。高中科学教师PI 将指导本科生和研究生进行原创性研究，并撰写教学文章，旨在培训他们了解与研究活动相一致的新科学发展。该研究的目标将是解决高温超导性的长期谜题的一些关键方面。量子材料中出现超导性的无间隙金属相，实验强烈表明，电子的量子运动在强关联金属中长距离受挫和纠缠，并且微观自由度（即电子和声子）相互交织。这项研究活动将开发新颖的非微扰理论方法来解决电子液体与其他集体自由度纠缠的问题，以揭示无间隙量子多体系统的普遍方面。PI 将制定。研究不依赖于明确定义的类电子（“准粒子”）激发的无间隙相的新方法为了解决其非平凡的动力学问题，PI将开发基于技术进步的新颖的理论技术。对受挫磁体、混沌量子多体系统中的热化以及不受费米子“符号问题”影响的数值精确算法的研究 PI 将建立在以下猜想的基础上：（i）相互作用的受挫液体提供。一个不平凡的起点，用于包含量子涨落的影响并描述先前未探索的无间隙相；以及（ii）金属常规中的电传输理论可以在广泛的中间温度范围内分解为具有通用性的充分“混沌”模型； PI 还将利用高度可控莫尔系统的最新突破，重点研究窄电子带与​​低能声子耦合的问题，使用精确的数值方法分析这些问题将为束缚提供一个重要的概念框架。汇集大量现有的高温超导体实验数据，并帮助指导寻找表现出类似现象的新材料。 PI 的教育和推广活动与研究相结合。 PI 将启动一个新的多元化播客系列。著名研究人员阵容，以提高公众和学生对该领域的兴奋程度的认识。 PI 将指导本科生和研究生进行原创研究，并撰写教学文章，旨在培训他们了解与新的科学发展相一致的知识。通过 STEM 教师计划，利用康奈尔大学现有的基础设施，PI 将为高中科学教师举办一系列研讨会，共同制定引人入胜的课程计划。该奖项反映了 NSF 的法定使命，并被认为是值得的。通过使用基金会的智力优势和更广泛的影响审查标准进行评估来提供支持。

项目成果

T-linear resistivity from magneto-elastic scattering: Application to PdCrO 2

磁弹性散射的 T 线性电阻率：在 PdCrO 2 中的应用

• DOI: 10.1073/pnas.2305609120
• 发表时间: 2023-09
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Mendez;Tulipman, Evyatar;Zhakina, Elina;Mackenzie, Andrew P.;Berg, Erez;Chowdhury, Debanjan
• 通讯作者: Chowdhury, Debanjan