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arXiv · 2104.02669

Suppressing Coherent Two-Qubit Errors via Dynamical Decoupling

Jiawei Qiu·Yuxuan Zhou·Chang-Kang Hu·Jiahao Yuan·Libo Zhang·Ji Chu·Wenhui Huang·Weiyang Liu·Kai Luo·Zhongchu Ni·Xianchuang Pan·Zhixuan Yang·Yimeng Zhang·Yuanzhen Chen·Xiu-Hao Deng·Ling Hu·Jian Li·Jingjing Niu·Yuan Xu·Tongxing Yan·Youpeng Zhong·Song Liu·Fei Yan·Dapeng Yu
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Abstract

Scalable quantum information processing requires the ability to tune multi-qubit interactions. This makes the precise manipulation of quantum states particularly difficult for multi-qubit interactions because tunability unavoidably introduces sensitivity to fluctuations in the tuned parameters, leading to erroneous multi-qubit gate operations. The performance of quantum algorithms may be severely compromised by coherent multi-qubit errors. It is therefore imperative to understand how these fluctuations affect multi-qubit interactions and, more importantly, to mitigate their influence. In this study, we demonstrate how to implement dynamical-decoupling techniques to suppress the two-qubit analogue of the dephasing on a superconducting quantum device featuring a compact tunable coupler, a trending technology that enables the fast manipulation of qubit--qubit interactions. The pure-dephasing time shows an up to ~14 times enhancement on average when using robust sequences. The results are in good agreement with the noise generated from room-temperature circuits. Our study further reveals the decohering processes associated with tunable couplers and establishes a framework to develop gates and sequences robust against two-qubit errors.

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Jiawei Qiu, Yuxuan Zhou, Chang-Kang Hu, Jiahao Yuan, Libo Zhang, Ji Chu, Wenhui Huang, Weiyang Liu, Kai Luo, Zhongchu Ni, Xianchuang Pan, Zhixuan Yang, Yimeng Zhang, Yuanzhen Chen, Xiu-Hao Deng, Ling Hu, Jian Li, Jingjing Niu, Yuan Xu, Tongxing Yan, Youpeng Zhong, Song Liu, Fei Yan, Dapeng Yu. 2021-04-06. Suppressing Coherent Two-Qubit Errors via Dynamical Decoupling. https://doi.org/10.1103/physrevapplied.16.054047

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