Topological Monopole Sources of Synthetic Gauge Fields using Spin-1 Bose Einstein Condensates

Topological and geometric structures in parameterized quantum systems play important roles spanning many areas of physics. We experimentally realize an artificial magnetic monopole using three states of an ultracold rubidium-87 ensemble, where the monopole charge is quantified by the first Chern number. By extending quantum simulations of U(1) monopole sources to regimes requiring spin–tensor–momentum coupling in the Hamiltonian, we access a richer topological and geometric landscape. We directly measure the Berry curvature and extract the first Chern number across distinct topological phases, observing a clear topological phase transition. Additional signatures of each phase are revealed through spin-texture measurements and Majorana-star trajectories. The persistence of the topological charge under Hamiltonian deformations, together with the power-law divergence of the associated synthetic vector field, provides strong additional evidence for the presence of a synthetic  monopole.