Dispersive Readout of a Few-Electron Double Quantum Dot with Fast rf Gate-Sensors

TL;DR

This paper demonstrates a dispersive gate-sensing technique for double quantum dots that offers comparable performance to traditional charge detectors, with potential advantages for scalable quantum computing readout.

Contribution

The authors introduce and benchmark a dispersive gate-sensing method for double quantum dots, eliminating the need for separate charge detectors.

Findings

Bandwidth of 10 MHz achieved

Charge sensitivity of 6.3 x 10^-3 e/√Hz

Comparable performance to quantum point contact detectors

Abstract

We report the dispersive charge-state readout of a double quantum dot in the few-electron regime using the in situ gate electrodes as sensitive detectors. We benchmark this gate-sensing technique against the well established quantum point contact (QPC) charge detector and find comparable performance with a bandwidth of 10 MHz and an equivalent charge sensitivity of 6.3 x 10-3 e/ \sqrt Hz. Dispersive gate-sensing alleviates the burden of separate charge detectors for quantum dot systems and promises to enable readout of qubits in scaled-up arrays.