Dynamic properties of superconducting weak links

A comprehensive theoretical picture of the dynamic properties of the order parameter and the quasiparticles in superconducting short weak links is presented. Both diffusion and inelastic scattering are found to be important in relaxing nonequilibrium populations. At low voltages a dissipative current, which is considerably larger than the normal ohmic current, is found and at higher voltages the maximum supercurrent is enhanced. These effects describe quantitatively well the foot structure in the $I-V$ characteristic observed experimentally by Octavio, Skocpol, and Tinkham.