Dynamics of sine-Gordon solitons in the annular Josephson junction

The annular Josephson junction allows for the study of undisturbed soliton (fluxon) motion in the absence of collisions. With new experimental methods and design we have realized for the first time a fully controllable way of introducing individual fluxons or antifluxons into such a system. This has allowed us to study multisoliton behavior and to make a comparison with existing soliton-chain perturbation theory. An unforeseen crossover in the dynamical behavior at high velocities is tentatively interpreted in terms of soliton bunching.