Single-shot readout of a driven hybrid qubit in a GaAs double quantum dot

TL;DR

This paper demonstrates high-fidelity, single-shot readout of a hybrid qubit in GaAs double quantum dots using energy-selective tunneling, enabling coherent control and potential application in other materials like silicon.

Contribution

It introduces a novel single-shot projective readout method for hybrid qubits in GaAs, achieving high fidelity and demonstrating coherent control with potential for broader material applicability.

Findings

Readout visibility of ~92.6% achieved.

High-fidelity single-shot projective readout demonstrated.

Coherent Rabi and Ramsey oscillations observed.

Abstract

We report a single-shot-based projective readout of a semiconductor hybrid qubit formed by three electrons in a GaAs double quantum dot. Voltage-controlled adiabatic transitions between the qubit operations and readout conditions allow high-fidelity mapping of quantum states. We show that a large ratio both in relaxation time vs. tunneling time (~ 50) and singlet-triplet splitting vs. thermal energy (~ 20) allow energy-selective tunneling-based spin-to-charge conversion with readout visibility ~ 92.6%. Combined with ac driving, we demonstrate high visibility coherent Rabi and Ramsey oscillations of a hybrid qubit in GaAs. Further, we discuss the generality of the method for use in other materials, including silicon.