Agenda

Résumé : Transport properties of superconductors are usually studied under conditions of current bias. A much broader spectrum of nonequilibrium states can emerge if the constraints imposed by current biasing techniques are relaxed. We will present results of experiments probing steady states of superconductors under conditions of intermediate bias, allowing the system to adjust to less restrictive boundary conditions. These measurements reveal a rich variety of non-equilibrium states in the current-voltage plane organized in a discrete set of bands. The problem of dissipation in superconductors is associated with variations in time of the order parameter. In disordered wires, finite resistivity arises from the generation of phase slip centres where the order parameter oscillates between its maximum value and zero. This phenomenon has been studied earlier in quasi-1D superconductors, and possibilities for utilizing it to design quantum devices have also been explored. Our measurements reveal signatures which share certain similarities with phase slips physics, although the dimensions are far removed from the 1D limit. We will discuss about further implications of these results for symmetry-breaking phenomena in non-linear electrical networks.