Monopoles, Scattering and Generalized Symmetries on a Quantum Computer

Quantum computers have advanced to the stage that interesting many-body quantum phenomena can be observed. A striking example is the magnetic monopole paradox, a problem that was only solved recently using the language of generalized symmetries. Here we demonstrate a quantum spin chain analogue of magnetic monopole scattering on Quantinuum System Model H2. We implement a novel protocol for preparing a localized quasiparticle wavepacket on top of the ground state. By combining this protocol with time evolution across a duality defect, we efficiently convert local particles into non-local string-like excitations. We demonstrate this particle-to-string conversion in the transverse-field Ising model and a symmetry-protected topological (SPT) phase of the cluster model. Our results establish duality defects and generalized symmetries as practical resources for preparing and probing non-local excitations on quantum hardware.