Quantum phase slips in superconducting wires with weak inhomogeneities

TL;DR

This paper estimates the amplitude of quantum phase slips at weak inhomogeneities in superconducting wires, highlighting the role of topological effects and the potential for controlled phase-slip localization.

Contribution

It provides a theoretical estimate for phase slip amplitudes at weak links modeled as coherent conductors, extending understanding beyond homogeneous wires.

Findings

Amplitude dominated by topological part of the action

Weak links naturally occur in homogeneous wires

Artificial weak links can localize phase slips

Abstract

Quantum phase slips are traditionally considered in diffusive superconducting wires which are assumed homogeneous. We present a definite estimate for the amplitude of phase slips that occur at a weak inhomogeneity in the wire where local resistivity is slightly increased. We model such a weak link as a general coherent conductor and show that the amplitude is dominated by topological part of the action. We argue that such weak links occur naturally in apparently homogeneous wires and adjust the estimate to that case. The fabrication of an artificial weak link would localize phase slips and facilitate a better control of the phase-slip amplitude.