Abstract
Spontaneous symmetry breaking (SSB) plays a central role in many areas of physics, from particle interactions to optical systems. Exceptional points (EPs), where system properties become degenerate, are often believed to occur together with SSB. Here we investigate the intricate relationship between SSB and a specific class of EPs across three distinct, real-world scenarios in nonlinear optics. In these systems, the two phenomena do not coincide; they occur at dislocated points in parameter space, but are interdependent. This recurring behavior across disparate platforms implies that such decoupling is not unique to these optical systems, but likely reflects a more general principle. Our results highlight the need for careful analysis of assumed correlations between SSB and EPs in both theoretical and applied contexts. They deepen our understanding of nonlinear dynamics in optical systems and prompt a broader reconsideration of contexts where EPs and SSB are thought to be interdependent.
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Acknowledgements
We thank Alexander Felski, George Ghalanos, Kyle Kawagoe, Jona Kayser, and Anton Montag for insightful discussions. We also acknowledge early, separate, and unpublished work by Michael T.M. Woodley exploring the connection between Jacobian EPs and SSB in counter-propagating light, which came to our attention late in the development of this project. L.H. acknowledges funding from the Max Planck Society (MPG) and the Centre national de la recherche scientifique (CNRS). J.T.G. and F.K.K. acknowledge support from the MPG Lise Meitner Excellence Program 2.0. L.H., J.T.G., and F.K.K. also acknowledge funding from the European Union’s ERC Starting Grant “NTopQuant” (101116680). L.H., A.G. and P.D’H. acknowledge support through the ERC Starting Grant “CounterLight” (756966). The views expressed are those of the authors and do not necessarily reflect those of the EU or the ERC. Neither the EU nor the granting authority can be held responsible for them.
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L.H. and J.T.G. carried out the majority of the calculations and theoretical work and should be considered co-first authors. They were supported by A.G. and J.F., who contributed to discussions and the analysis of results. F.K.K. and P.D’H. initiated the project and provided ongoing guidance, engaging in discussions with all authors. L.H. and J.T.G. prepared the manuscript with input from all co-authors.
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Hill, L., Gohsrich, J.T., Ghosh, A. et al. Exceptional points preceding and enabling spontaneous symmetry breaking. Commun Phys (2026). https://doi.org/10.1038/s42005-026-02491-0
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DOI: https://doi.org/10.1038/s42005-026-02491-0
