Nascent vortices in current-carrying hybrid superconducting bridge

We theoretically show that in a current-carrying hybrid superconductor (S)/normal metal (N) bridge there is a state with spatial oscillations of modulus of superconducting order parameter $\mathrm{\ensuremath{\Delta}}$ along the bridge and zero vorticity. This stationary state is realized at large currents, when proximity-induced superconductivity in the N layer is suppressed. With an increase of the current the number of oscillations of $\mathrm{\ensuremath{\Delta}}$ increases, which leads to oscillations of differential resistance or kinetic inductance of an SN bridge with normal or superconducting leads. At current the exceeding critical current ${I}_{\mathrm{c}}$, this spatially oscillating state transforms to periodically in time moving the vortex chain across the SN bridge. Because of these properties, we call such a state a nascent vortex state.