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Light emission from strongly driven many-body systems


Strongly driven systems of emitters offer an attractive source of light over broad spectral ranges up to the X-ray region. A key limitation of these systems is that the light they emit is mostly classical. We overcome this constraint by building a quantum-optical theory of strongly driven many-body systems, showing that the presence of correlations among the emitters creates emission of non-classical many-photon states of light. We consider the example of high-harmonic generation, by which a strongly driven system emits photons at integer multiples of the drive frequency. In the conventional case of uncorrelated emitters, the harmonics are in an almost perfectly multi-mode coherent state lacking any correlation between harmonics. By contrast, a correlation of the emitters before the strong drive is converted into non-classical features of the output light, including doubly peaked photon statistics, ring-shaped Wigner functions and correlations between harmonics. We propose schemes for implementing these concepts, creating the correlations between emitters via an interaction between them or their joint interaction with the background electromagnetic field. Our work paves the way towards the engineering of novel states of light over a broadband spectrum and suggests high-harmonic generation as a tool for characterizing correlations in many-body systems with attosecond temporal resolution.

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Fig. 1: Quantum theory of light emission by strongly driven many-body atomic systems.
Fig. 2: Many-body HHG.
Fig. 3: Quantum light from strongly driven super-radiant atoms.
Fig. 4: Quantum light from strongly driven interacting atoms.
Fig. 5: Correlated states of light.

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Data availability

All the data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

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The code is available from the authors upon reasonable request.


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We thank R. Bekenstein, O. Cohen, E. G. Dalla Torre, M. Even Tzur, M. Faran, R. Ruimy, E. Shahmoon and J. Sloan for insightful discussion on related topics and especially D. Malz and M. Kruger for discussions and for comments on the manuscript, and M. E. Tsur for illustrating state-of-the-art methods for simulating HHG with one-dimensional atomic models. A.P. acknowledges support from the Royal Society and from the AFOSR MURI programme (grant no. FA9550-21-1-0069), and hospitality at the Technical University of Munich (TUM).

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Correspondence to Nicholas Rivera or Ido Kaminer.

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Pizzi, A., Gorlach, A., Rivera, N. et al. Light emission from strongly driven many-body systems. Nat. Phys. 19, 551–561 (2023).

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