Quantum-interference device without Josephson junctions

Abstract

The behavior of a superconducting ring of homogeneous wire of transverse dimensions d\ensuremath{\ll}\ensuremath{\xi} and \ensuremath{\lambda} and uniform cross section connected to two long leads that carry a measuring current is analyzed using the nonlinear Ginzburg-Landau equations. When a magnetic field is present the system behaves like a superconducting quantum-interference device for appropriate values of ring sizes even though it has no Josephson junctions. A practical realization of such a device is within current technical capabilities.