Engineering quantum interference

Abstract

A model for describing the interference and diffraction of wave functions of one-dimensional Josephson array interferometers is presented. The derived expression for critical current modulations accounts for an arbitrary number of square junctions, the variable distance between these, and the variable size of their area. Predictions are tested on real arrays containing up to 20 equally spaced and identical junctions and on arrays shaped with peculiar geometries. A very good agreement with the modulations predicted by the model and the experimental results is obtained for all the tested configurations. It is shown that specific designs of the arrays generate significant differences in their static and dynamical (non-zero voltage) properties. The results demonstrate that the magnetic field dependence of Josephson supercurrents shows how interference and diffraction of macroscopic quantum wavefunctions can be manipulated and controlled. Published by AIP Publishing.

Magnetic flux quantum periodicity of the frequency of the on-chip detectable electromagnetic radiation from superconducting flux-flow-oscillators

“…When a B field is applied perpendicular to a planar one-dimensional JJ-array, magnetic vortices will enter the array in a form of Josephson expected to show a similar 0-periodicity (see Fig. 5 in the Supplementary Material) in agreement with the theoretical calculations for such JJ-arrays 24,25 . Indeed, at temperatures close to Tc=49 K we are in the low-inductance limit and the magnetic self-field effects due to the superconducting currents in the loops can be neglected.…”