Quantum Phase Transitions in Condensed Matter and Atomic Physics

这笔拨款支持基于量子相变研究的基本凝聚态物理的理论研究。还包括对原子物理和凝聚态物理之间的联系的研究；特别是对捕获的超冷原子系统的研究。量子相变是指在绝对零度温度下，由于载流子浓度、磁场强度或压力等调谐参数的变化而导致的物质状态的变化。在常规相之间的量子临界点附近对材料进行低温研究，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俘获的原子气体进行若干研究，分析许多量子相和转变中的一些，这些相和转变因最近的实验技术进步而成为可能。对于铜酸盐超导体，将对PI最近提出的在1/8载流子掺杂附近的超流-绝缘体转变理论进行扩展，以实现对高精度扫描隧道显微镜和中子散射实验的具体预测。该理论的一个核心要素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运动一样。为了获得热输运实验的预测，还需要研究邻近Mott绝缘体的密度波序和节块准粒子之间的相互作用。还需要研究金属间重费米子化合物中的磁性相变，探索在量子临界点出现解禁闭的分馏激发。对于捕获的超冷原子系统，描述了新的量子临界点，这些临界点可以在光学晶格上和费什巴赫共振附近进行实验探索。这些实验的详细理论将被开发出来。PI写了一本开创性的和广泛使用的教科书，量子相变，这是第二次印刷的平装本。PI正在编写第二版，将吸收这项研究的想法，并增加部分，以使更广泛的可及性。国际和平协会还为各种受众举办了关于这项研究的讲座和撰写文章。这种情况将继续下去。所有级别的学生都将参与这项研究。这个项目涉及凝聚态物理及其与原子物理的联系的理论研究。该项目是基于量子相变的。这些相变(想象一下水变成冰)发生在绝对零度，量子效应占主导地位。这些相变往往导致物质的新的和新的状态。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。国际和平研究所编写了一本开创性的、被广泛使用的教科书--量子相变，这是它的平装本的第二版。PI正在编写第二版，将吸收这项研究的想法，并增加部分，以使更广泛的可及性。国际和平协会还为各种受众举办了关于这项研究的讲座和撰写文章。这种情况将继续下去。所有级别的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.***