Confinement in quasi one-dimensional magnetically ordered quantum spin systems

准一维磁有序量子自旋系统中的限制

• 批准号: 456782977
• 负责人: Professor Dr. Hermann Boos
• 金额: --
• 依托单位: Arbeitsgruppe Kondensierte Materie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/456782977?language=en
• 关键词: Confinement; quasi; dimensional; magnetically; ordered

Confinement means that certain particles cannot exist in isolation, but must form bound states. The most famous example for this phenomenon is the confinement of quarks in hadrons. But confinement can also be observed in condensed matter systems. A most important example here is the confinement of spinons (= topological or kink excitations) in spin-chain compounds in which a linear attractive potential between the kinks is induced by a weak coupling between neighbouring magnetic chains. Kink confinement of this type was recently observed in neutron-scattering and terahertz-spectroscopy experiments in several ferro- and antiferromagnetic compounds. The main objective of the proposed research project is to perform analytic first-principal calculations of the experimentally relevant quantities, including the energy spectrum of the two-kink bound states and the dynamical structure factor. Our primary subject of interest will be the XXZ spin-1/2 chain, being a realistic model of a one-dimensional quantum anti-ferromagnet. Confinement of kinks takes place in the antiferromagnetic massive phase of this model, if it is perturbed by an integrability-breaking staggered magnetic field $h>0$ simulating the mean interaction with neighbouring chains. The integrability of the model at $h=0$ will make it possible to study the confinement phenomenon by means of a small-$h$ perturbative analysis based on the Bethe-Salpeter equation.

限制意味着某些粒子不能孤立地存在，而必须形成结合的状态。这种现象的最著名的例子是在哈德子中的夸克限制。但是在凝结物质系统中也可以观察到限制。这里最重要的例子是旋转链化合物中纺纱片（=拓扑或扭结激发）的限制，在这种化合物中，扭结之间的线性吸引力是由相邻磁链之间的弱耦合引起的。最近在几种铁磁性和抗铁磁化合物中的中子散射和Terahertz-Spectroscopicy实验中观察到了这种类型的纠结限制。拟议的研究项目的主要目的是对实验相关数量的分析初级计算，包括两键结合状态的能量光谱和动态结构因子。我们感兴趣的主要主题将是XXZ Spin-1/2链，是一维量子抗铁磁铁的现实模型。扭结的限制发生在该模型的抗磁性大规模阶段，如果它受到突破性的交错磁场的扰动，$ h> 0 $模拟与相邻链的平均相互作用。该模型在$ h = 0 $中的可集成性将使通过基于伯特 - 盐分方程的小$ h $扰动分析来研究限制现象。