Magnetized States of Quantum Spin Chains

量子自旋链的磁化状态

• 批准号: 9801742
• 负责人: Daniel Reich
• 金额: $ 27万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9801742&HistoricalAwards=false
• 关键词: Magnetized; States; Quantum; Spin; Chains

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. ***

这是一个实验研究项目，旨在表征准一维量子自旋系统的磁化状态，以及与磁场诱导的T = 0相变相关的关键特性。这项工作的目标是：(i)确定自旋链的磁化状态是否具有与理论预测的磁化强度成反比的不相称的长度尺度；（ii）为不断增长的量子临界现象理论结果提供实验对应。这项工作涉及一系列详细的实验，在具有良好特征的模型系统中，自旋哈密顿量可以通过磁场的应用可重复地变化，并且可以以受控的方式引入无序。将研究一些不同的准一维反铁磁体，包括自旋为S=1/2和S=1的线性链、键交替的线性链和自旋阶梯。这项研究涉及研究生和本科生，他们在实验凝聚态物理方面接受了广泛的教育，从样品制备到各种类型的实验和分析，再到结果的传播。这项研究的目标是通过对简单磁系统的详细实验研究来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，在这种磁体中，原子尺度的磁相互作用只在材料的一个方向上很强。这种一维性与量子力学相结合，产生了具有新颖而美丽特性的系统，在这些系统中，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方面获得广泛的教育，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。* * *