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

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

Wu, Yi Hsien (National Taiwan University; RIKEN)
Camenzind, Leon C. (RIKEN)
Noiri, Akito (RIKEN)
Takeda, Kenta (RIKEN)
Nakajima, Takashi (RIKEN)
Kobayashi, Takashi (RIKEN)
Chang, Chien Yuan (RIKEN)
Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre)
Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Tarucha, Seigo (RIKEN)

2024

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.

http://resolver.tudelft.nl/uuid:23b9219a-5b46-41b0-83de-021e07ada898

https://doi.org/10.1038/s41534-023-00802-9

2056-6387

NPJ Quantum Information, 10 (1)

Institutional Repository

journal article

© 2024 Yi Hsien Wu, Leon C. Camenzind, Akito Noiri, Kenta Takeda, Takashi Nakajima, Takashi Kobayashi, Chien Yuan Chang, A. Sammak, G. Scappucci, Seigo Tarucha