Aperiodic quantum optical materials

点击翻译按钮获取中文摘要

The vast majority of condensed matter physics research concerns periodic matter -- crystals. This is due to both the abundance of such materials, and the simplicity with which they can be characterised. However, at the frontiers of the subject we find the design and creation of artificial materials, where aperiodic structures offer advances beyond anything possible in crystalline matter. A notable example is in the field of topological quantum materials, where the 'tenfold way' quantifies restrictions on a material's behaviour according to certain symmetries and the number of dimensions in which it lives. Yet aperiodic 'quasicrystal' materials have been shown to behave like higher-dimensional crystals in this scheme, leading to the remarkable experimental observation of a four-dimensional quantum Hall effect in a 2D aperiodic waveguide array. Optical waveguides have been the principal route to realising new 'non-Hermitian' topological matter, which exchanges energy with its environment actively or dissipatively leading to optical gain or loss. The non-Hermitian feature enriches the dynamics of photons defining new topological states of matter. However, all demonstrations have been done only in periodic systems.This project concerns the theoretical design, and experimental creation, of new aperiodic photonic structures. In particular, the student will explore how photons travel in topological quasicrystals experiencing gain and loss (classical limit) and will further look at the dynamics of single photons in the same structures (quantum limit). Theoretical work will involve analytical calculations of the behaviour of non-Hermitian topological materials based on a tight-binding approach in aperiodic settings, as well as the use of computational modelling for the design of aperiodic structures. Experimental work will involve the creation and characterization of aperiodic waveguide arrays.