Magnetized States of Quantum Spin Chains

小行星9801742 这是一个实验研究计划，旨在表征磁化 准一维态 量子 自旋系统，以及与磁场相关的临界性质-诱导T = 0相变到这种状态。 这项工作的目标是（i）确定磁化状态的自旋链是否共享一个不相称的长度尺度，这是由理论预测的磁化强度成反比和（ii）提供一个实验对应的增长机构的理论结果量子临界现象。 这项工作涉及一系列详细的实验，以及表征模型系统中的自旋哈密顿量可以通过施加磁场，并在可控制的方式引入无序可重复地变化。 一些不同的准一维反铁磁体将被研究，包括线性链与自旋S=1/2和S=1，线性链与键交替，和自旋阶梯。 这项研究涉及研究生和本科生谁获得 实验凝聚态物理学的广泛教育，从样品制备到各种类型 从实验和分析到结果的传播。 本研究的目标是通过对简单磁系统的详细实验研究，增加对多体量子物理基本行为的理解。量子自旋链是一种磁体，其中原子尺度的磁相互作用仅在材料的一个方向上很强。 这种一维性与量子力学相结合，产生了具有新颖和美丽特性的系统，高度复杂的理论概念可以进行严格的实验测试。该研究涉及研究生和本科生，他们在实验凝聚态物理学方面获得了广泛的教育，从材料制备和各种尖端实验技术到复杂的数据分析和结果传播。 ***

9801742 Reich This is an experimental research program designed to characterize magnetized states of quasi--one--dimensional quantum spin systems, and the critical properties associated with the magnetic field--induced T = 0 phase--transitions into such states. The goals of this work are to (i) determine whether magnetized states of spin chains share an incommensurate length scale which is inversely proportional to magnetization as predicted by theory and (ii) to provide an experimental counterpart to the growing body of theoretical results about quantum critical phenomena. This work involves a series of detailed experiments on well- characterized model systems where the spin Hamiltonian can be varied reproducibly through the application of a magnetic field, and where disorder can be introduced in a controlled fashion. A number of different quasi-one-dimensional antiferromagnets will be investigated, including linear chains with spin S=1/2 and S=1, linear chains with bond alternation, and spin ladders. The research involves both graduate and undergraduate students who obtain a broad education in experimental condensed matter physics, from sample preparation through various types of experiments and analysis to the dissemination of results. %%% The goal of this research is to increase the understanding of the fundamental behavior of many-body quantum physics through detailed experimental studies of simple magnetic systems. Quantum spin chains are magnets in which the atomic-scale magnetic interactions are strong only in one direction in the material. This one-dimensionality coupled with quantum mechanics produces systems with novel and beautiful properties where highly sophisticated theoretical concepts can be put to rigorous experimental tests. The research involves both graduate and undergraduate students who obtain a broad education in experimental condensed matter physics, from materials pre paration and a variety of cutting-edge experimental techniques to sophisticated data analysis and the dissemination of results. ***