Manifestation of Resonance-Related Chaos in Coupled Josephson Junctions

TL;DR

This paper investigates chaos in coupled Josephson junctions, demonstrating how resonance-related chaos manifests in electrical signals and affects system behavior, with implications for high-temperature superconductor devices.

Contribution

It provides a detailed analysis of resonance-induced chaos in coupled Josephson junctions, including criteria for non-chaotic regions and connections to experimental observations.

Findings

Chaos manifests in electric charge dynamics due to parametric resonance.

The number of junctions affects the fine structure of current-voltage characteristics.

Criteria for non-chaotic regions are derived, explaining experimental power variations.

Abstract

Chaotic features of systems of coupled Josephson junctions are studied. Manifestation of chaos in the temporal dependence of the electric charge, related to a parametric resonance, is demonstrated through the calculation of the maximal Lyapunov exponent, phase-charge and charge-charge Lissajous diagrams and correlation functions. The number of junctions in the stack strongly influences the fine structure in the current voltage characteristics and a strong proximity effect results from the nonperiodic boundary conditions. The observed resonance-related chaos exhibits intermittency over a range of conditions and parameters. General features of the system are analyzed by means of a linearized equation and the criteria for a breakpoint region with no chaos are obtained. Such criteria could clarify recent experimental observations of variations in the power output from intrinsic Josephson junctions in high temperature superconductors.