Abstract
Artificial gauge fields allow uncharged particles such as photons to mimic the behaviour of charged particles subjected to magnetic fields, providing a powerful platform to alter the effective dynamics and exploring topological physics. Topological exciton-polariton lasers have attracted considerable interest, but often require strong magnetic fields to realise propagating topological edge states. Here we experimentally realise the topological Hall effect in a micron-scale micropillar chain by using an artificial gauge field, exploiting the circular polarisation of polaritons as an artificial dimension. Careful rotational alignment of elliptical micropillars induces strictly polarisation-dependent edge-state propagation, demonstrating non-reciprocal transport of the polariton pseudospins. Our results demonstrate that the dimensionality limitation of topological interface states as well as requirements for strong external magnetic fields in coupled topological laser arrays can be overcome. Our results open new ways towards the implementation of topological polariton lattices and related optically active devices with additional artificial dimension.
Data availability
The data generated in this study have been deposited in the wuedata database [wuedata.uni-wuerzburg.de]. The data is listed under this publication link: https://doi.org/10.58160/xfkn48dhnj1gbt2g.
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Acknowledgements
The Würzburg group acknowledges financial support by the German Research Foundation (DFG) under Germany’s Excellence Strategy-EXC2147 “ct.qmat” (project id 390858490) and within the project KL3124/3.1. T.C.H.L. was supported by the Singapore Ministry of Education (MOE) grant (MOE-MOET32023-0003) “Quantum Geometric Advantage”.
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S.W., J.B, J.D, C.G.M. and S.B. built the experimental set-up, performed the experiments and analysed the data. S.D. and P.G. grew the samples by molecular beam epitaxy. M.E., S.W. and J.B. realised the layout, etching and nanofabrication of the samples. S.M., R.B., T.C.H.L. and R.T. realised the theoretical calculations and numerical simulations. All authors participated in the scientific discussions about all aspects of the work. S.W. and S.K. wrote the original draft of the paper. All authors reviewed and edited the paper. T.C.H.L. and S.K. conceived the idea. S.H. and S.K. supervised the work.
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Widmann, S., Bellmann, J., Düreth, J. et al. Artificial gauge fields and dimensions in a polariton hofstadter ladder. Nat Commun (2026). https://doi.org/10.1038/s41467-026-68530-0
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DOI: https://doi.org/10.1038/s41467-026-68530-0
