Error detection in a tunable-barrier electron pump

TL;DR

This paper demonstrates a method to measure the electron loading dynamics in a tunable-barrier electron pump using a nearby charge sensor, enabling high-precision error rate testing of the pump.

Contribution

It introduces a technique for single-shot electron counting in a quantum dot pump with high fidelity, even at low current levels, enhancing metrological error analysis.

Findings

Successful measurement of electron number in a quantum dot using a charge sensor

Simulation results show optimized coupling enables high-fidelity single-shot detection

Method allows error rate testing of electron pumps with metrological precision

Abstract

We measure the average number of electrons loaded into an electrostatically-defined quantum dot (QD) operated as a tunable-barrier electron pump, using a point-contact (PC) charge sensor 1 micron away from the QD. The measurement of the electron number probes the QD loading dynamics even in the limit of slow gate voltage rise-times, when the pumped current is too small to measure. Using simulations we show that, with optimised QD-PC coupling, the experiment can make single-shot measurements of the number of electrons in the QD with sufficiently high fidelity to test the error rate of the electron pump with metrological precision.