Superconducting qubits map exotic four-dimensional topology in the lab

Using a superconducting qubit array, researchers implemented a hybrid analog-digital protocol to probe a four-dimensional topological object—a tensor monopole characterized by the Dixmier-Douady class of a real bundle gerbe—that lies beyond the reach of standard Berry-phase methods. When perturbed, this point-like singularity splits into a nodal ring carrying a first Euler class charge; further dimensional reduction yields 3D Euler dipoles governed by a topological sum rule that guarantees flat bands inherit nontrivial topology. The results extend the known zoo of topological monopoles and provide a concrete experimental route for studying non-Abelian quantum geometry and higher-order gauge theory on programmable quantum hardware.