Stochastic resonance in thermally bistable Josephson weak-links and micro-SQUIDs

TL;DR

This paper investigates stochastic resonance phenomena in thermally bistable Josephson weak-links and micro-SQUIDs, demonstrating noise-enhanced signal detection and potential applications in magnetic sensing.

Contribution

It introduces a two-state model to explain stochastic resonance in Josephson weak-links and demonstrates its use to improve micro-SQUID magnetic field sensing.

Findings

Observation of stochastic resonance in Josephson weak-links

Enhanced signal-to-noise ratio in micro-SQUID sensors

Validation of a two-state model for thermal bi-stability

Abstract

Constriction-based Josephson weak-links display a thermal bi-stability between two states exhibiting zero and finite voltages. This manifests in experiments either as hysteresis in weak-links current voltage characteristics or as random telegraphic signal in voltage. In the latter case, a noise-driven amplification of a sinusoidal excitation of the device is observed, at frequencies matching the characteristic switching frequency in telegraphic signal, a phenomenon known as stochastic resonance. The observed behavior is understood using a two-state model of stochastic resonance and is exploited to illustrate an enhanced signal-to-noise-ratio in a micro-SQUID as a magnetic field sensor.