Non-Abelian lattice gauge fields in photonic synthetic frequency dimensions Cheng, Dali Wang, Kai Roques-Carmes, Charles Lustig, Eran Long, Olivia Y. Wang, Heming Fan, Shanhui ddc:530 Non-Abelian gauge fields provide a conceptual framework to describe particles having spins, underlying many phenomena in electrodynamics, condensed-matter physics and particle physics. Lattice models of non-Abelian gauge fields allow us to understand their physical implications in extended systems. The theoretical importance of non-Abelian lattice gauge fields motivates their experimental synthesis and explorations. Photons are fundamental particles for which artificial gauge fields can be synthesized, yet the demonstration of non-Abelian lattice gauge fields for photons has not been achieved. Here we demonstrate SU(2) lattice gauge fields for photons in the synthetic frequency dimensions, a playground to study lattice physics in a scalable and programmable way. In our lattice model, we theoretically observe that homogeneous non-Abelian lattice gauge potentials induce Dirac cones at time-reversal-invariant momenta in the Brillouin zone. We experimentally confirm the presence of non-Abelian lattice gauge fields by two signatures: linear band crossings at the Dirac cones, and the associated direction reversal of eigenstate trajectories. We further demonstrate a non-Abelian scalar lattice gauge potential that lifts the degeneracies of the Dirac cones. Our results highlight the implications of non-Abelian lattice gauge fields in topological physics, and provide a starting point for demonstrations of emerging non-Abelian physics in the photonic synthetic dimensions. Our results may also benefit photonic technologies by providing controls of photon spins and pseudo-spins in topologically non-trivial ways. Springer Nature 2025 info:eu-repo/semantics/article doc-type:article article http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/21548 Cheng D, Wang K, Roques-Carmes C, et al. Non-Abelian lattice gauge fields in photonic synthetic frequency dimensions. <i>Nature</i>. 2025;637(8044):52-56. doi:<a href="https://doi.org/10.1038/s41586-024-08259-2">10.1038/s41586-024-08259-2</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1038/s41586-024-08259-2 info:eu-repo/semantics/altIdentifier/issn/0028-0836 info:eu-repo/semantics/altIdentifier/e-issn/1476-4687 info:eu-repo/semantics/altIdentifier/arxiv/2406.00321 info:eu-repo/semantics/altIdentifier/pmid/39743600 info:eu-repo/semantics/openAccess