A self-calibrating superconducting pair-breaking detector

TL;DR

This paper introduces a self-calibrating superconducting detector that precisely measures Cooper pair breaking events by detecting single electrons, with applications in high-frequency phonon detection and quantum sensing.

Contribution

The paper presents the first experimental realization of a self-calibrating Cooper pair-breaking detector based on a mesoscopic superconducting island, demonstrating accurate single-electron detection independent of device parameters.

Findings

Detector accurately measures single-electron events per broken Cooper pair

Device operates effectively with less than 10 fW of dissipated power

Experimental results agree with analytical and numerical models

Abstract

We propose and experimentally demonstrate a self-calibrating detector of Cooper pair depairing in a superconductor based on a mesoscopic superconducting island coupled to normal metal leads. On average, exactly one electron passes through the device per broken Cooper pair, independent of the absorber volume, device or material parameters. The device operation is explained by a simple analytical model and verified with numerical simulations in quantitative agreement with experiment. In a proof-of-concept experiment, we use such a detector to measure the high-frequency phonons generated by another, electrically decoupled superconducting island, with a measurable signal resulting from less than 10 fW of dissipated power.