Single-Shot Readout of a Driven Hybrid Qubit in a GaAs Double Quantum Dot.

Jang, Wonjin; Cho, Min-Kyun; Jang, Hyeongyu; Kim, Jehyun; Park, Jaemin; Kim, Gyeonghun; Kang, Byoungwoo; Jung, Hwanchul et al. · Nano Lett · 2021

basic_science · Level V

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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) allows energy-selective tunneling-based spin-to-charge conversion with a readout visibility of ≈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.