High-fidelity resonant gating of a silicon-based quantum dot hybrid qubit

Abstract

We implement resonant single qubit operations on a semiconductor hybrid qubit hosted in a three-electron Si/SiGe double quantum dot structure. By resonantly modulating the double dot energy detuning and employing electron tunnelling-based readout, we achieve fast (>100 MHz) Rabi oscillations and purely electrical manipulations of the three-electron spin states. We demonstrate universal single qubit gates using a Ramsey pulse sequence as well as microwave phase control, the latter of which shows control of an arbitrary rotation axis on the X-Y plane of the Bloch sphere. Quantum process tomography yields rotation gate fidelities higher than 93 (96)% around the X (Z) axis of the Bloch sphere. We further show that the implementation of dynamic decoupling sequences on the hybrid qubit enables coherence times longer than 150 ns.