# Chiral quantum optics in the bulk of photonic quantum Hall systems

## TL;DR

This paper explores how chiral waveguide modes in a 2D photonic lattice with synthetic magnetic and electric fields enable directional photon emission and reabsorption, facilitating reconfigurable quantum networks.

## Contribution

It introduces a novel mechanism for symmetric photon emission and reabsorption in bulk photonic systems with synthetic gauge fields, enabling flexible quantum emitter networks.

## Key findings

- Identification of critical coupling conditions for symmetric photon emission.
- Demonstration of reabsorption of photons without time-dependent control.
- Generalization to arbitrary in-plane synthetic potentials.

## Abstract

We study light-matter interactions in the bulk of a two-dimensional photonic lattice system, where photons are subject to the combined effect of a synthetic magnetic field and an orthogonal synthetic electric field. In this configuration, chiral waveguide modes appear in the bulk region of the lattice, in direct analogy to transverse Hall currents in electronic systems. By evaluating the non-Markovian dynamics of emitters that are coupled to those modes, we identify critical coupling conditions, under which the shape of the spontaneously emitted photons becomes almost fully symmetric. Combined with a directional, dispersionless propagation, this property enables a complete reabsorption of the photon by another distant emitter, without relying on any time-dependent control. We show that this mechanism can be generalized to arbitrary in-plane synthetic potentials, thereby enabling flexible realizations of re-configurable networks of quantum emitters with arbitrary chiral connectivity.