In-flight detection of few electrons using a singlet-triplet spin qubit

TL;DR

This paper demonstrates that a singlet-triplet spin qubit can detect fewer than five flying electrons in quantum Hall edge channels, showcasing its potential for single-electron detection in quantum electronics.

Contribution

It experimentally shows the ultrasensitive charge detection capability of a spin qubit for flying electrons, advancing quantum electron optics in semiconductor circuits.

Findings

Detected less than five flying electrons with average measurement

Established the spin qubit as a fast, ultrasensitive charge detector

Paved the way for single-shot detection of individual flying electrons

Abstract

We investigate experimentally the capacitive coupling between a two-electron singlet-triplet spin qubit and flying electrons propagating in quantum Hall edge channels. After calibration of the spin qubit detector, we assess its charge sensibility and demonstrate experimentally the detection of less than five flying electrons with average measurement. This experiment demonstrates that the spin qubit is an ultrasensitive and fast charge detector with the perspective of a future single shot-detection of a single flying electron. This work opens the route toward quantum electron optics experiments at the single electron level in semiconductor circuits.