Single-shot latched readout of a quantum dot qubit using barrier gate pulsing

TL;DR

This paper introduces a barrier gate pulsing technique for single-shot readout of quantum dot qubits with a single reservoir, simplifying the process and improving measurement speed.

Contribution

It presents a novel pulsing method for dynamic tunnel rate control, enabling effective latched readout with a single reservoir in quantum dot qubits.

Findings

Enabled qubit state latching using barrier gate pulsing

Reduced qubit reset time in measurements

Demonstrated effectiveness with silicon/beryllium quantum dots

Abstract

Latching techniques are widely used to enhance readout of qubits. These methods require precise tuning of multiple tunnel rates, which can be challenging to achieve under realistic experimental conditions, such as when a qubit is coupled to a single reservoir. Here, we present a method for single-shot measurement of a quantum dot qubit with a single reservoir using a latched-readout scheme. Our approach involves pulsing a barrier gate to dynamically control qubit-to-reservoir tunnel rates, a method that is readily applicable to the latched readout of various spin-based qubits. We use this method to enable qubit state latching and to reduce the qubit reset time in measurements of coherent Larmor oscillations of a Si/SiGe quantum dot hybrid qubit.