Physical mechanisms of timing jitter in photon detection by current carrying superconducting nanowires

We studied timing jitter in the appearance of photon counts in meandering nanowires with different fractional amount of bends. Timing jitter, which is the probability density of the random time delay between photon absorption in current-carrying superconducting nanowire and appearance of the normal domain, reveals two different underlying physical scenarios. In the deterministic regime, which is realized at large currents and photon energies, jitter is controlled by position dependent detection threshold in straight parts of meanders and decreases with the current. At small photon energies, jitter increases and its current dependence disappears. In this probabilistic regime jitter is controlled by Poisson process in that magnetic vortices jump randomly across the wire in areas adjacent to the bends.