Hamiltonian phase error in resonantly driven CNOT gate above the fault-tolerant threshold

Yi Hsien Wu*, Leon C. Camenzind*, Akito Noiri, Kenta Takeda, Takashi Nakajima, Takashi Kobayashi, Chien Yuan Chang, Amir Sammak, Giordano Scappucci, Seigo Tarucha*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Because of their long coherence time and compatibility with industrial foundry processes, electron spin qubits are a promising platform for scalable quantum processors. A full-fledged quantum computer will need quantum error correction, which requires high-fidelity quantum gates. Analyzing and mitigating gate errors are useful to improve gate fidelity. Here, we demonstrate a simple yet reliable calibration procedure for a high-fidelity controlled-rotation gate in an exchange-always-on Silicon quantum processor, allowing operation above the fault-tolerance threshold of quantum error correction. We find that the fidelity of our uncalibrated controlled-rotation gate is limited by coherent errors in the form of controlled phases and present a method to measure and correct these phase errors. We then verify the improvement in our gate fidelities by randomized benchmark and gate-set tomography protocols. Finally, we use our phase correction protocol to implement a virtual, high-fidelity, controlled-phase gate.

Original languageEnglish
Article number8
Number of pages9
JournalNPJ Quantum Information
Issue number1
Publication statusPublished - 2024


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