English

Logical Magic State Preparation with Fidelity Beyond the Distillation Threshold on a Superconducting Quantum Processor

Quantum Physics 2023-06-01 v2

Abstract

Fault-tolerant quantum computing based on surface code has emerged as an attractive candidate for practical large-scale quantum computers to achieve robust noise resistance. To achieve universality, magic states preparation is a commonly approach for introducing non-Clifford gates. Here, we present a hardware-efficient and scalable protocol for arbitrary logical state preparation for the rotated surface code, and further experimentally implement it on the \textit{Zuchongzhi} 2.1 superconducting quantum processor. An average of \hhl{0.8983±0.00020.8983 \pm 0.0002} logical fidelity at different logical states with distance-three is achieved, \hhl{taking into account both state preparation and measurement errors.} In particular, \hhl{the magic states Aπ/4L|A^{\pi/4}\rangle_L, HL|H\rangle_L, and TL|T\rangle_L are prepared non-destructively with logical fidelities of 0.8771±0.00090.8771 \pm 0.0009 , 0.9090±0.00090.9090 \pm 0.0009 , and 0.8890±0.00100.8890 \pm 0.0010, respectively, which are higher than the state distillation protocol threshold, 0.859 (for H-type magic state) and 0.827 (for T -type magic state).} Our work provides a viable and efficient avenue for generating high-fidelity raw logical magic states, which is essential for realizing non-Clifford logical gates in the surface code.

Keywords

Cite

@article{arxiv.2305.15972,
  title  = {Logical Magic State Preparation with Fidelity Beyond the Distillation Threshold on a Superconducting Quantum Processor},
  author = {Yangsen Ye and Tan He and He-Liang Huang and Zuolin Wei and Yiming Zhang and Youwei Zhao and Dachao Wu and Qingling Zhu and Huijie Guan and Sirui Cao and Fusheng Chen and Tung-Hsun Chung and Hui Deng and Daojin Fan and Ming Gong and Cheng Guo and Shaojun Guo and Lianchen Han and Na Li and Shaowei Li and Yuan Li and Futian Liang and Jin Lin and Haoran Qian and Hao Rong and Hong Su and Shiyu Wang and Yulin Wu and Yu Xu and Chong Ying and Jiale Yu and Chen Zha and Kaili Zhang and Yong-Heng Huo and Chao-Yang Lu and Cheng-Zhi Peng and Xiaobo Zhu and Jian-Wei Pan},
  journal= {arXiv preprint arXiv:2305.15972},
  year   = {2023}
}

Comments

In this version, we do not employ readout error mitigation strategies (in the previous version, we use readout transition matrix to mitigate the measurement error) to remove measurement errors because we believe it provides a more predictive assessment of the actual fidelity when generating and consuming magic states for a non-Clifford gate, as consuming the state involves measurement

R2 v1 2026-06-28T10:45:53.522Z