Experimental observation of spatiotemporal wave forms of all possible types of soliton-antisoliton interactions in Josephson transmission lines

We report the first observation of soliton-antisoliton (fluxon-antifluxon) collision processes of all types (annihilation, passing through, and pair creation) in a discrete Josephson transmission line of niobium. These collision processes were directly measured not only in time, but also in space by a Josephson sampling system with precise control of the collision point. Negative phase shifts, contrary to the analytic solution for the sine-Gordon equation, were observed and attributed to the dissipation.