Detection of Tiny Mechanical Motion by Means of the Ratchet Effect

TL;DR

This paper introduces a novel dc measurement scheme for detecting tiny mechanical motions in nanoelectromechanical resonators using the ratchet effect in a three-junction SQUID, enhancing sensitivity through biasing.

Contribution

It presents a new position detection method leveraging the ratchet effect in a SQUID, enabling sensitive, dc-based measurements of mechanical motion.

Findings

The ratchet response varies with the resonator's position.

Biasing with ac current enhances detection sensitivity.

Feasibility is demonstrated in existing experimental setups.

Abstract

We propose a position detection scheme for a nanoelectromechanical resonator based on the ratchet effect. This scheme has an advantage of being a dc measurement. We consider a three-junction SQUID where a part of the superconducting loop can perform mechanical motion. The response of the ratchet to a dc current is sensitive to the position of the resonator and the effect can be further enhanced by biasing the SQUID with an ac current. We discuss the feasibility of the proposed scheme in existing experimental setups.