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CAREER: Towards Predictive Modeling of Emergent Correlations and Dynamics in Strongly Interacting Quantum Matter

职业：强相互作用量子物质中的涌现相关性和动力学的预测建模

基本信息

批准号：
2046570
负责人：
Hitesh Changlani
金额：
$ 54.73万
依托单位：
Florida State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-05-01 至 2026-04-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2046570&HistoricalAwards=false
关键词：
CAREER Towards Predictive Modeling Emergent

项目摘要

NONTECHNICAL SUMMARYThis CAREER award supports an integrated research, education, and outreach program in theoretical and computational condensed-matter physics. The main aim of the project is to advance our understanding of quantum matter composed of electrons that interact strongly with one another. These systems are at the heart of many fundamental physical phenomena, ranging from magnetism to superconductivity (flow of electrons with no resistance). The problem at hand can be explained with an analogy from everyday life: one might learn to play individual musical notes yet not know how to put them together to produce a melody. Similarly, we now know the quantum-mechanical laws that govern individual electrons and nuclei but find it difficult to predict the emergent behavior of many such interacting components. Just as a collection of atoms organizes itself into a solid, liquid, or gas depending on external conditions, electronic matter can exist in "valence-bond solid," "quantum spin liquid," or "Fermi gas" phases, among other possibilities. Reliably predicting the behavior of electronic systems will aid future technologies and searches for quantum materials with desirable properties.The PI and his team will investigate geometrically "frustrated" magnetic materials found in nature and laboratories worldwide. Frustration arises when multiple spatial arrangements of electron "spin" orientations each have similar collective energy, so there is no clear winner. This feature results in unusual quantum dynamics that have been observed in modern-day experiments but for which theoretical explanations are limited. Thus, a major focus of this proposal is to develop efficient computer algorithms to predict how such quantum materials behave under different conditions (change in temperature and application of a magnetic field) and how they respond to external probes (involving light or neutrons). The PI and his team will also employ existing state-of-the-art numerical methods to address outstanding fundamental questions associated with this class of magnetic materials.The PI's education and outreach programs are synergistically coupled to his research. The focus is on communicating the workings of computational methods for quantum systems to graduate students and the wider research community. With input from expert authors, the PI and his team will write an e-book that will train the next generation to embrace a rapidly evolving lexicon of quantum-mechanical concepts. Through multiple outreach activities at his home institution, including open houses and public seminars, the PI will convey the importance of quantum physics in our everyday lives. To inspire more students to pursue higher education and careers in science, the PI will conduct tutoring and mentoring activities at a local K-12 school that enrolls a large number of students from underrepresented minority groups.TECHNICAL SUMMARYThis CAREER award supports an integrated research, education, and outreach program in theoretical and computational condensed-matter physics. The main aim of the project is to advance our understanding of strongly correlated quantum systems, those not approximated by a non-interacting model of electrons. Reliably predicting their behavior from computer simulations remains a major challenge in physics, chemistry, and materials science. Additionally, the quantum mechanics of correlated systems in the time domain, central to both equilibrium and non-equilibrium phenomena, is not as well-characterized and understood as its time-independent counterpart. Many experiments collect a wealth of dynamical information, but one needs theoretical inputs to interpret them. For example, evidence for fractionalized spinons in one dimension is indirectly inferred from comparison of neutron scattering data and theory.The PI and his team will investigate geometrically frustrated magnets, which harbor valence-bond-solid, quantum-spin-liquid, and spin-nematic phases. Efforts in this area will further the PI's goal of predicting properties such as transition temperatures, magnetization profiles, and dynamical responses, given minimal knowledge of the quantum material.The PI and his team will perform research in the following directions:1. They will numerically simulate and analyze spin dynamics at zero and finite temperature for spin-orbit-coupled, spin-ice, and spin-1 magnets on kagome and pyrochlore lattices in an applied magnetic field. Comparisons to measurements from dynamical probes such as inelastic neutron scattering and terahertz spectroscopy experiments will be carried out.2. They will explore a toy lattice model of frustration that harbors "three-colored" exact ground states. The model offers a way to understand non-equilibrium dynamical phenomena (such as glassiness) and has potential pedagogical value.3. They will develop the "density-matrix-downfolding" technique, a form of Hilbert-space operator renormalization, to generate effective Hamiltonians. This method will help connect real materials to strongly-correlated lattice models.The PI's education program will focus on communicating the workings of computational methods for quantum systems to graduate students and the wider research community. With input from expert authors, the PI and his team will write an e-book focused on many-body-wavefunction and density-matrix based approaches. Through multiple outreach activities at his home institution, including open houses and public seminars, the PI will convey the importance of quantum physics in our everyday lives. To inspire more students to pursue higher education and careers in science, the PI will conduct tutoring and mentoring activities at a local K-12 school that enrolls a large number of students from underrepresented minority groups.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和计算凝聚态物理领域的综合研究、教育和推广计划。该项目的主要目的是增进我们对由彼此强烈相互作用的电子组成的量子物质的理解。这些系统是许多基本物理现象的核心，从磁性到超导性（无阻力的电子流动）。当前的问题可以用日常生活中的类比来解释：一个人可能学会演奏单个音符，但不知道如何将它们组合在一起产生旋律。同样，我们现在知道控制单个电子和原子核的量子力学定律，但发现很难预测许多此类相互作用成分的涌现行为。正如原子集合根据外部条件将自身组织成固体、液体或气体一样，电子物质也可以以“价键固体”、“量子自旋液体”或“费米气相”等形式存在。可靠地预测电子系统的行为将有助于未来的技术和寻找具有理想特性的量子材料。首席研究员和他的团队将研究在世界各地的自然界和实验室中发现的几何“受挫”磁性材料。当电子“自旋”方向的多个空间排列各自具有相似的集体能量时，就会出现挫败感，因此没有明显的赢家。这一特征导致了不寻常的量子动力学，这种动力学已在现代实验中观察到，但理论解释有限。因此，该提案的一个主要重点是开发有效的计算机算法来预测此类量子材料在不同条件（温度变化和磁场应用）下的行为以及它们如何响应外部探针（涉及光或中子）。 PI 和他的团队还将采用现有的最先进的数值方法来解决与此类磁性材料相关的突出基本问题。PI 的教育和推广计划与其研究相结合。重点是将量子系统计算方法的工作原理传达给研究生和更广泛的研究界。根据专家作者的意见，首席研究员和他的团队将编写一本电子书，培训下一代接受快速发展的量子力学概念词汇。通过在他所在机构的多项外展活动，包括开放日和公共研讨会，PI 将传达量子物理学在我们日常生活中的重要性。为了激励更多的学生追求高等教育和科学职业，PI 将在当地一所 K-12 学校开展辅导和指导活动，该学校招收了大量来自弱势群体的学生。技术摘要该职业奖支持理论和计算凝聚态物理领域的综合研究、教育和推广计划。该项目的主要目的是增进我们对强相关量子系统的理解，这些系统不是用非相互作用的电子模型来近似的。通过计算机模拟可靠地预测它们的行为仍然是物理、化学和材料科学领域的一个重大挑战。此外，时域相关系统的量子力学是平衡和非平衡现象的核心，但它不像与时间无关的对应系统那样得到很好的表征和理解。许多实验收集了大量的动力学信息，但需要理论输入来解释它们。例如，通过中子散射数据和理论的比较间接推断出一维中分数化自旋子的证据。 PI和他的团队将研究几何受挫磁体，这些磁体具有价键固体、量子自旋液体和自旋向列相。鉴于对量子材料的了解很少，该领域的努力将进一步推动 PI 预测诸如转变温度、磁化曲线和动态响应等特性的目标。PI 和他的团队将在以下方向进行研究：1。他们将在零温度和有限温度下对戈薇和烧绿石晶格上的自旋轨道耦合、自旋冰和自旋 1 磁体在外加磁场中的自旋动力学进行数值模拟和分析。将与非弹性中子散射和太赫兹光谱实验等动态探针的测量结果进行比较。2．他们将探索一种包含“三色”精确基态的挫败玩具晶格模型。该模型提供了一种理解非平衡动力学现象（如玻璃态）的方法，具有潜在的教学价值。3．他们将开发“密度矩阵下折叠”技术，这是希尔伯特空间算子重整化的一种形式，以生成有效的哈密顿量。这种方法将有助于将真实材料与强相关晶格模型连接起来。PI 的教育计划将侧重于向研究生和更广泛的研究界传达量子系统计算方法的工作原理。根据专家作者的意见，PI 和他的团队将编写一本电子书，重点介绍基于多体波函数和密度矩阵的方法。通过在他所在机构的多项外展活动，包括开放日和公共研讨会，PI 将传达量子物理学在我们日常生活中的重要性。为了激励更多学生追求高等教育和从事科学事业，PI 将在当地一所 K-12 学校开展辅导和指导活动，该学校招收了大量来自代表性不足的少数群体的学生。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。