Stochastic resonance in an RF SQUID with shunted ScS junction

TL;DR

This paper demonstrates that RF SQUIDs with shunted ScS junctions exhibit stochastic resonance at any small loop inductance and critical current, due to their unique bistable potential energy, unlike traditional SIS junctions.

Contribution

It provides the first numerical simulation analysis of stochastic dynamics in ScS RF SQUIDs, highlighting their distinct resonance behavior compared to SIS-based SQUIDs.

Findings

ScS RF SQUIDs show stochastic resonance at arbitrary small parameters.

The potential energy of ScS junctions always has a barrier, enabling bistability.

Differences in stochastic amplification between ScS and SIS junctions are discussed.

Abstract

Using a point (superconductor-constriction-superconductor, ScS) contact in a single-Josephson-junction superconducting quantum interference device (RF SQUID) provides stochastic resonance conditions at any arbitrary small value of loop inductance and contact critical current, unlike SQUIDs with more traditional tunnel (superconductor-insulator-superconductor, SIS) junctions. This is due to the unusual potential energy of the ScS RF SQUID which always has a barrier between two wells thus making the device bistable. This paper presents the results of a numerical simulation of the stochastic dynamics of the magnetic flux in an ScS RF SQUID loop affected by band-limited white Gaussian noise and low-frequency sine signals of small and moderate amplitudes. The difference in stochastic amplification of RF SQUID loops incorporating ScS and SIS junctions is discussed.