Physical Review Letters
American Physical Society
A Hamiltonian system is said to have nontrivial monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit in angular momentum-energy space. This process has been predicted to have consequences which can be seen in dynamical systems, called dynamical monodromy. Using an apparatus consisting of a spherical pendulum subject to magnetic potentials and torques, we observe nontrivial monodromy by the associated topological change in the evolution of a loop of trajectories.
Nerem, M. P.; Salmon, D.; Aubin, S.; and Delos, John B., Experimental Observation of Classical Dynamical Monodromy (2018). Physical Review Letters, 120(13).