Stationary phase slip state in quasi-one-dimensional rings

TL;DR

This paper investigates a unique stationary phase slip state in quasi-one-dimensional rings where the superconducting order parameter vanishes at one point, highlighting conditions under which this state can be stabilized and observed experimentally.

Contribution

It introduces the concept of a stationary phase slip state in non-uniform rings and discusses how it can be stabilized in practical experimental setups.

Findings

The phase slip state involves a $\pi$ phase jump at the zero of the order parameter.

In uniform rings, this state is unstable and saddle-point.

Non-uniformities can stabilize the phase slip state, enabling experimental realization.

Abstract

The nonuniform superconducting state in a ring in which the order parameter vanishing at one point is studied. This state is characterized by a jump of the phase by $\pi$ at the point where the order parameter becomes zero. In uniform rings such a state is a saddle-point state and consequently unstable. However, for non-uniform rings with e.g. variations of geometrical or physical parameters or with attached wires this state can be stabilized and may be realized experimentally.