Local Moment and Heavy Fermion Physics

这项理论研究属于重电子物理领域。这一课题在当前相关材料的研究中占据了一个不起眼但至关重要的位置。许多基本问题，如磁性是如何产生的，以及围绕量子临界发展的非费米液态金属的性质，都是整个领域亟待解决的问题。将要进行的部分工作是由一系列新的实验推动的，这些实验将重费米子材料微调到量子相变。开发新技术、新模型和新概念来理解重电子材料及其临界行为是本研究的核心内容。场调谐量子临界性：未筛选的Kondo杂质模型提供了场调谐量子临界性的一个例子，具有可以连续驱动到零的费米温度。使用该模型的晶格泛化作为起点，我们将模拟磁性重电子系统在其接近量子临界的过程中的演化。受挫重电子材料：我们将研究在Hund的耦合过渡金属氧化物中受挫和近藤效应的相互作用。隐序和节点电荷密度波的形成：我们将研究两个波段系统来发展URu2Si2的隐序理论。一种新的Z2 Majorana局部矩物理方法：这将允许我们从Majorana传播子读取自旋相关器，避免在传统方案中遇到的顶点校正困难。该方法将应用于单杂质和点阵Kondo模型。赝隙系统中状态相关的密度：受天体物理学中布朗-特维斯干涉测量的类比启发，我们将开发一种从扫描隧道显微镜中测量的状态波动密度中提取信息顺序参数相关的方法。此基金支持强相关重电子系统的物理理论研究。这项研究处于现代凝聚态物理学的前沿，将为基础物理学的基础做出贡献。研究生和博士后研究人员的参与将确保未来几代理论家将在这些重要领域得到培训。像许多凝聚态物理一样，这项研究也有可能影响新材料的开发和应用

This theoretical research is in the area of heavy electron physics. This subject occupies a modest yet vital corner in current research into correlated materials. Many of the fundamental questions, such as how magnetism emerges and the nature of the non-Fermi liquid metal that develops around quantum criticality, are pressing problems to the field as a whole. Part of the work to be undertaken is motivated by a new range of experiments that fine-tune heavy fermion materials to a quantum phase transition. The development of new techniques, models and concepts to understand heavy electron materials and their critical behavior is a central element of this research.The following subjects will be studied:Field-tuned quantum criticality: The underscreened Kondo impurity model provides an example of field-tuned quantum criticality, with a Fermi temperature which can be driven continuously to zero. Using a lattice generalization of this model as a starting point, we will model the evolution of magnetically heavy electron systems in their approach to quantum criticality.Frustrated heavy electron materials: We will study the interplay of frustration and the Kondo effect in Hund's coupled transition metal oxides.Hidden order and nodal charge density wave formation: We will study two band systems to develop a theory for hidden order in URu2Si2.A new Z2 Majorana approach to local moment physics: This will allow us to read-off spin correlators from the Majorana propagator, avoiding vertex correction difficulties encountered in conventional schemes. This new method will be applied to the single impurity and lattice Kondo model.Density of state correlations in pseudogap systems: Inspired by the analogy with the Brown-Twiss interferometry of astrophysics, we will develop a method to extract information order parameter correlations from density of state fluctuations measured in scanning tunneling microscopy.%%%This grant supports theoretical research on the physics of strongly correlated heavy electron systems. The research is at the forefront of modern condensed matter physics and will contribute to the foundations of fundamental physics. The participation of graduate students and postdoctoral research associates will ensure that future generations of theorists will be trained in these important areas. Like much of condensed matter physics, the research also has the potential to influence the development and applications of new materials.***