Quantum Hall phases emerging from atom\u2013photon interactions

Alexander V Poshakinskiy,Nikita A Olekhno,Chaohong Lee,Alexander N Poddubny,Janet Zhong,Yuri S Kivshar,Yongguan Ke

doi:10.1038/s41534-021-00372-8

Abstract

We reveal the emergence of quantum Hall phases, topological edge states, spectral Landau levels, and Hofstadter butterfly spectra in the two-particle Hilbert space of an array of periodically spaced two-level atoms coupled to a waveguide (waveguide quantum electrodynamics). While the topological edge states of photons require fine-tuned spatial or temporal modulations of the parameters to generate synthetic magnetic fields and the quantum Hall effect, here we demonstrate that a synthetic magnetic field can be self-induced solely by atom–photon interactions. The fact that topological order can be self-induced in what is arguably the simplest possible quantum structure shows the richness of these waveguide quantum electrodynamics systems. We believe that our findings will advance several research disciplines including quantum optics, many-body physics, and nonlinear topological photonics, and that it will set an important reference point for the future experiments on qubit arrays and quantum simulators.

Highlights

Recent technological advances have underpinned the rapid development of cavity quantum electrodynamics (QED) and circuit QED, which allow to exploit quantum properties of light for applications in information processing[1,2,3]
Waveguide QED is promising for many applications in quantum information processing
In waveguide QED setups, photons become strongly coupled to atoms and create light-matter quasi-particles called polaritons

Summary

Introduction

Recent technological advances have underpinned the rapid development of cavity quantum electrodynamics (QED) and circuit QED, which allow to exploit quantum properties of light for applications in information processing[1,2,3]. It can allow us to efficiently generate[14,15,16], detect[17], slow[18], and store quantum light[19]. It is useful as a platform for quantum simulators of complex many-mode physics[20,21]. A crucial advantage of waveguide QED systems is that they can exhibit long-range coupling between distant atoms mediated by light. This makes the dispersion of atomic excitations and their interactions markedly different from those in the typical case of nearest-neighbor coupling in circuit QED1 or in conventional condensed matter systems. The goal of this work is to explore the potential of waveguide

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Conclusion