Chirality-driven delocalization in disordered waveguide-coupled quantum arrays

TL;DR

This paper investigates how chiral coupling and disorder influence eigenstate localization in quantum arrays, revealing a complex phase diagram with transitions from localization to delocalization driven by asymmetry and disorder.

Contribution

It introduces a theoretical analysis of the interplay between chirality and disorder, uncovering nontrivial phase transitions and edge localization phenomena in quantum emitter arrays.

Findings

Transition from Anderson localization to delocalization with increasing asymmetry

Sharpening of phase transition despite strong disorder

Edge localization induced by chirality

Abstract

We study theoretically the competition between directional asymmetric coupling and disorder in a one-dimensional array of quantum emitters chirally coupled through a waveguide mode. Our calculation reveals highly nontrivial phase diagram for the eigenstates spatial profile, nonmonotonously depending on the disorder and directionality strength. The increase of the coupling asymmetry drives the transition from Anderson localization in the bulk through delocalized states to chirality-induced localization at the array edge. Counterintuitively, this transition is not smeared by strong disorder but becomes sharper instead. Our findings could be important for the rapidly developing field of the waveguide quantum electrodynamics, where the chiral interactions and disorder play crucial roles.