Shot noise in ultrathin superconducting wires

Abstract

Quantum phase slips (QPS) may produce non-equilibrium voltage fluctuations in current-biased superconducting nanowires. Making use of the Keldysh technique and employing the phase-charge duality arguments we investigate such fluctuations within the four-point measurement scheme and demonstrate that shot noise of the voltage detected in such nanowires may essentially depend on the particular measurement setup. In long wires the shot noise power decreases with increasing frequency $\Omega$ and vanishes beyond a threshold value of $\Omega$ at $T \to 0$