Fast and High Excitation Transport in Waveguide Quantum Electrodynamics

TL;DR

This paper demonstrates a method for achieving fast and high excitation transport in waveguide QED systems using chirally-coupled atomic arrays, highlighting the role of subradiant states and nonreciprocal decay channels.

Contribution

It introduces a novel approach employing chirally-coupled atomic arrays to enhance excitation transport via waveguide-mediated interactions, emphasizing the importance of nonreciprocal decay channels.

Findings

Enhanced excitation transport due to subradiant eigenstates.

Optimal configurations require finite nonreciprocal decay channels.

Transport efficiency depends on atom number and coupling directionality.

Abstract

Waveguide quantum electrodynamics (wQED) with underlying collective and long-range atom-atom interactions has led to many distinct dynamical phenomena, including modified collective radiations and intriguing quantum correlations. It stands out as a unique platform to illustrate correlated photon transport, as well as to promise applications in quantum information processing. Here we manifest a fast and high atomic excitation transport by employing two separated chirally-coupled atomic arrays. This enhanced waveguide-mediated transport of excitations emerges due to the dominance of few subradiant right eigenstates that are spectrally isolated and spatially localized in the system's dynamics. Contrary to the instinct of applying the cascaded systems with unidirectional couplings to expedite direct and high excitation transport, the optimal system configurations in open wQED systems demand slight or finite nonreciprocal decay channels to facilitate energy transport by exploiting waveguide-mediated couplings. We also investigate the effect of the couplings' directionality and the scaling of atom number on the transport properties. Our results showcase the wide applicability in wQED platforms and provide insights into quantum engineering and quantum information applications.