Dynamics and Correlations in Frustrated Magnets.

受挫磁铁是相互作用的自旋的集体阶段。它们是关联材料的主要例子，展示了丰富多样的现象，超越了我们对以朗道理论为特征的对称破缺相以及局域有序参数的规范理解。特别是，量子自旋液体(QSL)的特征是出现了分数级激发和拓扑性质，例如基态简并和拓扑保护的边缘激发。QSL对于我们从根本上理解多体相是有意义的，但也具有技术应用的潜力。尽管经过了几十年的研究，但仍然没有明确确定的材料实现了QSL。然而，在过去的几年里，已经发现了几个有前途的候选系统。此外，在理论方面，已经发明了一些精确可溶的模型系统，允许在严格的水平上理解QSL的性质。本论文旨在通过探索聚合模型哈密顿的动力学性质来弥合理论和实验之间的差距。其目的是为了更好地了解QSL的潜在相关性，并在实验中促进它们的诊断和表征。

Frustrated magnets are collective phases of interacting spins. They are prime examples of Correlated Materials displaying a rich variety of phenomena beyond our canonical understanding of symmetry breaking phases characterised by Landau theory as well as local order parameters. In particular, Quantum Spin Liquids (QSL) are characterised by the emergence of fractionalised excitations and topological properties, e.g. ground state degeneracies and topologically protected edge excitations. QSLs are of interest for our fundamental understanding of many-body phases but have also potential for technological application. Despite decades of research there is still no unambiguously identified materials realisation of a QSL. However, the last few years have seen the discovery of several promising candidate systems. Moreover, on the theoretical side a number of exactly soluble model systems have been invented which allow to understand QSL properties on a rigorous level. This thesis aims at bridging the gap between these recent developments in theory and experiments by exploring the dynamical properties of paradigmatic model Hamiltonians. The goal is to gain a better understanding of the underlying correlations of QSLs and to facilitate their diagnosis and characterisation in experiments.