Dual Fraunhofer interference and charge fluctuations in long quantum phase slip wires

Abstract

Charge interference (Aharonov-Casher effect) in a long superconducting quantum phase slip wire is considered, and from this the "dual"Fraunhofer interference effect (dual to the critical current modulation of a short Josephson junction in an external magnetic field) is derived. The device that can be used to observe this effect is proposed. Furthermore, the impact of wire inhomogeneities, charge disorder, and noise on the phase slip amplitude is investigated. Although intrinsically protected against small fluctuations, the Aharonov-Casher interference resulting from jumps of random offset charges and quasiparticles can result in significant fluctuations of the measured current-voltage characteristics of the quantum phase slip wire, similar to the effects of Joule heating when averaged out over many fluctuations. Possible ways to identify and mitigate such disorder are discussed.