Quantum Phase Transitions in Condensed Matter and Atomic Physics

该补助金支持基于量子相变研究的基础凝聚态物理学的理论研究。 量子相变是指在绝对零度时，物质的状态发生变化，这一变化是由载流子浓度、磁场强度或压强等参数的变化所驱动的。 在常规相之间的量子临界点附近的低温下对材料的研究已被证明是寻找具有新物理性质的新量子相的肥沃土壤。 将对金属间化合物和捕获的原子气体进行一些研究，分析许多量子相和跃迁中的一些，这些量子相和跃迁已通过实验技术的最新进展而变得容易获得。 对于铜酸盐超导体，PI最近的理论在1/8载流子掺杂附近的超流-绝缘体转变的扩展将进行，以允许高精度扫描隧道显微镜和中子散射实验的具体预测。 该理论的一个核心组成部分是超导体涡旋所扮演的新角色，它的行为就像量子粒子在磁场中移动。 也要研究的是密度波之间的相互作用的顺序接近莫特绝缘体和节点准粒子的目的是获得预测的热传输实验。 也要研究的是金属间重费米子化合物的磁相变，探索量子临界点处的去精细化分数激发的出现。 对于被囚禁的超冷原子系统，新的量子临界点已经被描述，可以在光学晶格和Feshbach共振附近进行实验探索。 这些实验的详细理论将被开发。PI已经写了一本开创性的和广泛使用的教科书，量子相变，这是在其第二次印刷作为平装本。 PI正在编写第二版，将纳入这项研究的想法，并增加章节以实现更广泛的可访问性。 PI还为各种各样的观众提供了关于这项研究的讲座和文章。 这将继续下去。 各级学生都将参与这项研究。% 该项目涉及凝聚态物理学的理论研究及其与原子物理学的联系。 该项目基于量子相变。 这些是相变（想想水变成冰），发生在绝对零度的温度下，量子效应占主导地位。 这些相变往往导致新的和新颖的物质状态。 这些研究是现代凝聚态物理学基本核心领域的一部分，但有朝一日可能会找到技术应用。PI写了一本开创性和广泛使用的教科书，量子相变，这是在其第二次印刷作为平装本。 PI正在编写第二版，其中将纳入这项研究的想法，并添加部分以实现更广泛的可访问性。 PI还为各种各样的观众提供了关于这项研究的讲座和文章。 这将继续下去。 各级学生都将参与这项研究。*

This grant supports theoretical research on fundamental condensed matter physics based on the study of quantum phase transitions. Also included are studies of the connections between atomic physics and condensed matter physics; in particular studies of systems of trapped ultracold atoms.Quantum phase transitions are changes in state of matter at the absolute zero of temperature, driven by changes in a tuning parameter such as carrier concentration, magnetic field strength, or pressure. Studies of materials at low temperatures in the vicinity of quantum critical points between conventional phases have proven to be fertile ground for finding new quantum phases with novel physical properties. A number of studies will be undertaken of intermetallic compounds and trapped atomic gases analyzing some of the many quantum phases and transitions that have become accessible by recent advances in experimental technologies. For the cuprate superconductors, extensions of the PI's recent theory for the superfluid-insulator transition in the vicinity of 1/8 carrier doping will be made, to allow specific predictions for high precision scanning tunneling microscopy and neutron scattering experiments. A central ingredient of the theory is the novel role played by the vortices of the superconductor, which behave like quantum particles moving in a magnetic field. Also to be studied is the interplay between the density wave order of the proximate Mott insulator and the nodal quasiparticles with the aim of obtaining predictions for thermal transport experiments. Also to be studied are magnetic phase transitions in the intermetallic heavy fermion compounds, exploring the emergence of deconfined fractionalized excitations at the quantum critical point. For the trapped ultracold atomic systems, new quantum critical points have been described that can be explored experimentally on optical lattices and near a Feshbach resonance. Detailed theories of these experiments will be developed.The PI has written a seminal and widely used textbook, Quantum Phase Transitions, that is in its second printing as a paperback. The PI is working on a second edition that will incorporate ideas from this research, and adding sections to enable wider accessibility. The PI has also presented lectures and written articles on this research for a wide variety of audiences. This will continue. Students at all levels will be involved with this research.%%% This project involves theoretical studies of condensed matter physics and its connections to atomic physics. The project is based on quantum phase transitions. These are phase transitions (think of water turning to ice) that occur at absolute zero of temperature where quantum effects dominate. These phase transitions often lead to new and novel states of matter. These studies are part of the fundamental core area of modern condensed matter physics, and yet may someday find technological applications. The PI has written a seminal and widely used textbook, Quantum Phase Transitions, that is in its second printing as a paperback. The PI is working on a second edition that will incorporate ideas from this research, and adding sections to enable wider accessibility. The PI has also presented lectures and written articles on this research for a wide variety of audiences. This will continue. Students at all levels will be involved with this research.***