Vortex dynamics in inhomogeneous superconducting films

A vortex moving without dissipation in a superconducting film containing random inhomogeneities is shown to have a strictly periodic trajectory. By exploiting a new percolation analogy, the voltage noise power and the electrical resistivity due to a vortex are described at low frequencies in the zero-drag limit by the universal form P()p2, with p20.4. The introduction of dissipation into the vortex equations of motion modifies this form and causes resistivity to appear at zero frequency. Analogous effects should be observable in inhomogeneous superfluid He4 films.