Detection of noise-corrupted sinusoidal signals with Josephson junctions

TL;DR

This paper explores how Josephson junctions can be used to detect sinusoidal signals hidden in noise by analyzing escape times, offering two detection strategies that leverage the junctions' sensitivity.

Contribution

It introduces two novel detection strategies using Josephson junctions for sinusoidal signals in noise, highlighting their resonant activation features.

Findings

Escape time is highly sensitive to small signals

Proposed detection strategies are suboptimal but effective in certain cases

Resonant activation enhances detection capabilities

Abstract

We investigate the possibility of exploiting the speed and low noise features of Josephson junctions for detecting sinusoidal signals masked by Gaussian noise. We show that the escape time from the static locked state of a Josephson junction is very sensitive to a small periodic signal embedded in the noise, and therefore the analysis of the escape times can be employed to reveal the presence of the sinusoidal component. We propose and characterize two detection strategies: in the first the initial phase is supposedly unknown (incoherent strategy), while in the second the signal phase remains unknown but is fixed (coherent strategy). Our proposals are both suboptimal, with the linear filter being the optimal detection strategy, but they present some remarkable features, such as resonant activation, that make detection through Josephson junctions appealing in some special cases.