Abstract:

Phase slips are topological fluctuation events that carry the superconducting order-parameter field between distinct current carrying states and impart a non-zero resistance to superconducting nanowires. Although thermally activated phase slips are relatively well-understood, quantum phase slips resulting via tunneling of the order parameter, had remained elusive so far. By presenting our theory for very recent experiments on current-biased nanowires, I will argue that the distribution of switching currents (at which the wire stochastically switches from a superconductive to normal state) can provide a powerful probe for phase-slip events. Based on a detailed fitting of the experimental data, I will further conclude that there is a low temperature regime in which the experiments are in fact probing individual quantum phase slip events.