Quasiparticle cooling of a single-Cooper-pair-transistor

TL;DR

This paper demonstrates quasiparticle cooling in a single-Cooper-pair-transistor using a superconducting tunnel junction, reducing quasiparticle density and tunneling rates, with potential benefits for superconducting quantum devices.

Contribution

It introduces a method to directly cool quasiparticles in a superconducting transistor, improving coherence by reducing quasiparticle effects.

Findings

Quasiparticle density is reduced through cooling.

Quasiparticle tunneling rate decreases with cooling.

Radio-frequency reflectometry measures the tunneling rate.

Abstract

A superconducting tunnel junction is used to directly extract quasiparticles from one of the leads of a single-Cooper-pair-transistor. The consequent reduction in quasiparticle density causes a lower rate of quasiparticle tunneling onto the device. This rate is directly measured by radio-frequency reflectometry. Local cooling may be of direct benefit in reducing the effect of quasiparticles on coherent superconducting nanostructures.