Local Moment and Heavy Fermion Physics

该奖项支持重电子材料和局部矩物理的理论研究和教育。理解这些低能量材料所需的新概念，将在许多情况下在能量和温度上扩大，以描述过渡金属材料（如铜基和铁基超导体）中的相关现象。这一领域的许多关键问题都涉及到重要的基础问题，如量子临界物理学、各向异性超导机制和非费米液体行为的起源。受到两种新的、不寻常的重费米子超导体发现的激励，PI将应用他最近开发的一种新型大n展开来研究重电子超导性。重电子量子临界的新见解和近藤自旋液体材料的发现激发了PI开始对近藤晶格的相图进行一系列新的研究。最近在多铁氧化物中发现了一个磁调谐临界端点。PI将进行一项新的研究计划，研究多铁性材料的场调谐量子临界性。对“硬凝聚态物理”各个方面的研究对新物理概念的发展和未来材料的新思路都起着至关重要的推动作用。例如，量子临界点向成核超导和其他物质新相的显著趋势对材料的发展具有极大的兴趣；另一方面，量子相变的新普适性类具有重大的基础意义，并且像它们在统计力学中的经典前辈一样，可能在宇宙学和粒子物理学领域得到推广和未来的应用。这是学生既能学习到理论物理的先进方法，又能与实验物理和真实材料保持密切接触的绝佳场所。PI坚定地致力于物理学的多样性，长期以来一直支持物理学领域的女性。目前有两名女研究生在他的小组工作。该奖项支持被称为重电子材料的一类材料的理论研究和教育。流动量子态中的电子和稀土或锕系元素原子周围的量子态的相互作用导致了一种不寻常的金属态，其性质与教科书一致。量子相变的存在使这些材料的性质变得更加复杂。量子相变发生在温度的绝对零度，但在一定温度范围内都能感受到其强大的影响。PI将建立并使用他开发的一种很有前途的新方法，以深入了解本课程中最近发现的两种超导体材料和更普遍的重电子材料。PI还将研究这些材料的超导态。PI将进一步探索量子相变在新发现的多铁性材料中的作用，多铁性材料是未来电子器件中很有前途的一类材料。对超导态和让位给超导的异常金属态的研究为材料研究和超导奠定了理论基础。这一知识可能会导致利用超导体的能力，以一种实用的方式在没有到非常低的功耗下携带电流，从而显著节省能源。PI坚定地致力于物理学的多样性，长期以来一直支持物理学领域的女性。目前有两名女研究生在他的小组工作。

TECHNICAL SUMMARYThis award supports theoretical research and education on heavy electron materials and local moment physics. The new concepts required to understand these low-energy materials, will, in many cases scale up in energy and temperature to describe related phenomenon in transition Metal materials, such as copper and iron-based superconductors. Many of the key questions in this area touch upon issues of fundamental importance, such as the physics of quantum criticality, mechanisms of anisotropic superconductivity, and the origins of non-Fermi liquid behavior. Motivated by the discovery of two new and unusual heavy fermion superconductors, the PI will apply a new type of large-N expansion for heavy electron superconductivity that he has recently developed. Fresh insights in heavy electron quantum criticality and the discovery of a Kondo spin liquid material inspire the PI to embark on a new set of investigations into the phase diagram of the Kondo lattice. A magnetically tuned critical end point in a multiferroic oxide has recently been discovered. The PI will pursue a new research program to study field-tuned quantum criticality in multiferroic materials.Research into the various aspects of "hard condensed matter physics" plays an essential driving role in both the development of new physics concepts, and new ideas for materials of the future. For example, the remarkable tendency of quantum critical points to nucleate superconductivity and other new phases of matter is of great interest to materials development; on the other hand, the new universality classes of quantum phase transition are of great fundamental interest and, like their classical predecessors in statistical mechanics, may enjoy generalization and future application in the realm of cosmology and particle physics. This is wonderful area for students to learn the advanced methods of theoretical physics, while maintaining an intimate contact with experimental physics and real materials.The PI is strongly committed to diversity in physics, with a long record of support for women in physics. Two women graduate students are currently working in his group. NON-TECHNICAL SUMMARYThis award supports theoretical research and education on a class of materials known as heavy electron materials. The interplay of electrons in itinerant quantum states and quantum states localized around a rare-earth or actinide atom leads to an unusual metallic state with properties that are consistent with the textbooks. The properties of these materials are further complicated by the existence of quantum phase transitions - phase transitions that occur at the absolute zero of temperature but with a powerful influence that can be felt over a range of temperature. The PI will build on and use a promising new method that he has developed to gain insight into two recently discovered materials in this class that are superconductors and into heavy electron materials more generally. The PI will also study the superconducting states of these materials. The PI will further explore the role quantum phase transitions play in newly discovered multiferroic materials which are a promising class of materials for future electronic devices. The study of the superconducting states and the unusual metallic states which give way to superconductivity contributes to the intellectual foundations of materials research and superconductivity. This knowledge may lead to harnessing the ability of superconductors to carry electric current with no to very low power dissipation in a practical way leading to significant energy savings. The PI is strongly committed to diversity in physics, with a long record of support for women in physics. Two women graduate students are currently working in his group.