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  • Open Access

Robust Superradiance and Spontaneous Spin Ordering in Disordered Waveguide Quantum Electrodynamics

Xin H. H. Zhang1,2,3,*, Daniel Malz4, and Peter Rabl1,2,3

  • *Contact author: physicsxinzhang@gmail.com
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PRX Quantum 7, 033034 – Published 19 August, 2026

DOI: https://doi.org/10.1103/97jv-13r6

Abstract

We study the collective emission of a disordered array of N excited two-level atoms into a one-dimensional photonic waveguide. In the perfectly ordered case, where atoms are spaced by exact integer multiples of the wavelength, the system exhibits the characteristic superradiant burst with a peak emission rate scaling as N2. Using large-scale semiclassical simulations, we find that this key signature of superradiance remains asymptotically robust under strong spatial and spectral disorder, but also exhibits subtle finite-size scaling toward this limit. To explain our observations, we provide an analytical variational estimate for the maximal decay rate, which tightly bounds the numerical results and reveals how disorder shapes the collective decay. Specifically, we find that even in the presence of strong disorder, the spins tend to self-organize spontaneously according to their locations, which overall optimizes constructive interference effects and explains the emergence of mirror-asymmetric correlations in superradiant decay. These findings resolve important open questions regarding the existence and nature of superradiance in strongly disordered arrays and offer valuable insights for understanding collective quantum optical phenomena in realistic systems.

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Popular Summary

What doesn’t kill atomic superradiance makes the atoms smarter. Superradiance—where a group of excited atoms acts coherently and collectively to emit an intense burst of photons—was thought to require global phase alignment for constructive interference. It was thus expected that strong disorder would disrupt this cooperativity and kill superradiance. Surprisingly, we find that atoms are much “smarter” than previously thought. By studying disordered atoms decaying into a one-dimensional photonic waveguide, we show that even in the presence of strong disorder, atoms can self-organize their orientations in a way that aligns with the disorder. This emergent pattern still produces constructive interference, enabling rapid collective emission and preserving superradiance. Our work provides an essential mechanism for understanding collective behaviors in imperfect quantum platforms, which will be relevant for building novel quantum light sources and for collectively enhanced sensing applications.

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PRX Quantum 7, 033034– Published 19 August, 2026
  • Received 21 October 2025
  • Revised 23 April 2026
  • Accepted 10 July 2026
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