Microsecond resolution of quasiparticle tunneling in the single-Cooper-pair-transistor

TL;DR

This paper demonstrates radio-frequency measurements of a single-Cooper-pair-transistor with microsecond resolution, revealing quasiparticle poisoning events and their energetics, including an effective quasiparticle temperature.

Contribution

It introduces a method to observe quasiparticle poisoning in real-time and characterizes the energetics of poisoning and un-poisoning processes.

Findings

Quasiparticle poisoning events occur on microsecond timescales.

Energetics of poisoning and un-poisoning are quantified.

An effective quasiparticle temperature parameter is introduced.

Abstract

We present radio-frequency measurements on a single-Cooper-pair-transistor in which individual quasiparticle poisoning events were observed with microsecond temporal resolution. Thermal activation of the quasiparticle dynamics is investigated, and consequently, we are able to determine energetics of the poisoning and un-poisoning processes. In particular, we are able to assign an effective quasiparticle temperature to parameterize the poisoning rate.