Emergent Quasiperiodicity from Polariton-phonon Hybrid Excitations in Waveguide Quantum Optomechanics

Abstract: We investigate polariton-phonon hybrid excitations, which describe the collective excitations of emitter-photon polaritons and vibrational phonons, in a periodic array of vibrating two-level emitters interacting with waveguide photons. We demonstrate the emergence of an interaction-induced quasiperiodic structure caused by the interplay between phonon scatterings and waveguide-mediated long-range couplings. This quasiperiodicity fundamentally changes the excitation characteristics in the subradiant regime, which feature an appearance of topological edge states and a transition between ergodic and multifractal excitations. A possible realization consisting of an array of laser-cooled atoms trapped near an optical nanofiber is also proposed. Our results demonstrate the possibility of utilizing vibrations as a novel degree of freedom in the exploration of many-body physics with waveguide quantum electrodynamics systems.