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; Hsi-Sheng Goan; Seigo Tarucha

arXiv · 2307.09031

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·Hsi-Sheng Goan·Seigo Tarucha

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Abstract

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 the gate errors are useful to improve the 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.

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Yi-Hsien Wu, Leon C. Camenzind, Akito Noiri, Kenta Takeda, Takashi Nakajima, Takashi Kobayashi, Chien-Yuan Chang, Amir Sammak, Giordano Scappucci, Hsi-Sheng Goan, Seigo Tarucha. 2023-07-18. Hamiltonian Phase Error in Resonantly Driven CNOT Gate Above the Fault-Tolerant Threshold. https://arxiv.org/abs/2307.09031

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