Light-matter interactions near photonic Weyl points

TL;DR

This paper provides a comprehensive theoretical analysis of how quantum emitters interact with Weyl photons in photonic systems, revealing unique emission behaviors and tunable interactions near Weyl points.

Contribution

It introduces a detailed theoretical framework for understanding light-matter interactions near photonic Weyl points, including emission dynamics and conditions for effective spin models.

Findings

Asymmetric emission dynamics when detuned from Weyl frequency

Highly collimated emission regimes observed

Enhanced tunability of interactions with staggered terms

Abstract

Weyl photons appear when two three-dimensional photonic bands with linear dispersion are degenerate at a single momentum point, labeled as Weyl point. These points have remarkable properties such as being robust topological monopoles of Berry curvature as well as an associated vanishing density of states. In this work, we report on a systematic theoretical study of the quantum optical consequences of such Weyl photons. First, we analyze the dynamics of a single quantum emitter coupled to a Weyl photonic bath as a function of its detuning with respect to the Weyl point and study the corrresponding emission patterns, using both perturbative and exact treatments. Our calculations show an asymmetric dynamical behavior when the emitter is detuned away from the Weyl frequency, as well as different regimes of highly collimated emission, which ultimately translate in a variety of directional collective decays. Besides, we find that the incorporation of staggered mass and hopping terms in the bath Hamiltonian both enriches the observed phenomenology and increases the tunability of the interaction. Finally, we analyze the competition between the coherent and dissipative components of the dynamics for the case of two emitters and derive the conditions under which an effective interacting spin model description is valid.