Topological transitions and Anderson localization of light in disordered atomic arrays

TL;DR

This paper investigates how disorder affects topological phases and localization of light in atomic honeycomb lattices, revealing disorder-induced phase transitions and the suppression or emergence of localized modes due to topological effects.

Contribution

It demonstrates how disorder can induce topological phase transitions and create or suppress localized photonic modes in atomic arrays, highlighting the interplay of topology and disorder.

Findings

Disorder can induce topological phase transitions in atomic lattices.

Topological band structure suppresses Anderson localization within the band gap.

Disorder can generate localized modes inside a topologically trivial spectrum.

Abstract

We explore the interplay of disorder and topological phenomena in honeycomb lattices of atoms coupled by the electromagnetic field. On the one hand, disorder can trigger transitions between distinct topological phases and drive the lattice into the topological Anderson insulator state. On the other hand, the nontrivial topology of the photonic band structure suppresses Anderson localization of modes that disorder introduces inside the band gap of the ideal lattice. Furthermore, we discover that disorder can both open a topological pseudogap in the spectrum of an otherwise topologically trivial system and introduce spatially localized modes inside it.