Photon Bound States in Coupled Waveguides

TL;DR

This paper investigates photon bound states in coupled waveguides with emitters, revealing their molecular-like behavior and identifying new classes of bound states, advancing understanding of photon interactions in quantum photonics.

Contribution

It introduces a novel configuration of coupled waveguides with emitters, demonstrating that photon bound states behave as rigid molecules and discovering new classes of these states.

Findings

Photon bound states behave like rigid molecules.

Photons tend to tunnel collectively rather than individually.

New classes of bound states are identified.

Abstract

Photon bound states have been identified as particular solutions to the scattering of two photons from a single emitter, but from these results the full nature of these states remains elusive. We study a novel, clear and unambiguous signature that these bound states are truly bound. To this end we consider a new configuration of close-by waveguides, each chirally coupled to two-level emitters. We show that in this system the photon bound states behave like rigid molecules, where photons do not tunnel individually but rather collectively, such that there is rarely a single photon in each waveguide. We further identify new classes of bound states in this system.