Bao Zehang, Xu Shibo, Song Zixuan, Wang Ke, Xiang Liang, Zhu Zitian, Chen Jiachen, Jin Feitong, Zhu Xuhao, Gao Yu, Wu Yaozu, Zhang Chuanyu, Wang Ning, Zou Yiren, Tan Ziqi, Zhang Aosai, Cui Zhengyi, Shen Fanhao, Zhong Jiarun, Li Tingting, Deng Jinfeng, Zhang Xu, Dong Hang, Zhang Pengfei, Liu Yang-Ren, Zhao Liangtian, Hao Jie, Li Hekang, Wang Zhen, Song Chao, Guo Qiujiang, Huang Biao, Wang H
School of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, and Zhejiang Key Laboratory of Micro-nano Quantum Chips and Quantum Control, Zhejiang University, Hangzhou, China.
Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2024 Oct 12;15(1):8823. doi: 10.1038/s41467-024-53140-5.
Greenberger-Horne-Zeilinger (GHZ) states, also known as two-component Schrödinger cats, play vital roles in the foundation of quantum physics and the potential quantum applications. Enlargement in size and coherent control of GHZ states are both crucial for harnessing entanglement in advanced computational tasks with practical advantages, which unfortunately pose tremendous challenges as GHZ states are vulnerable to noise. Here we propose a general strategy for creating, preserving, and manipulating large-scale GHZ entanglement, and demonstrate a series of experiments underlined by high-fidelity digital quantum circuits. For initialization, we employ a scalable protocol to create genuinely entangled GHZ states with up to 60 qubits, almost doubling the previous size record. For protection, we take a different perspective on discrete time crystals (DTCs), originally for exploring exotic nonequilibrium quantum matters, and embed a GHZ state into the eigenstates of a tailor-made cat scar DTC to extend its lifetime. For manipulation, we switch the DTC eigenstates with in-situ quantum gates to modify the effectiveness of the GHZ protection. Our findings establish a viable path towards coherent operations on large-scale entanglement, and further highlight superconducting processors as a promising platform to explore nonequilibrium quantum matters and emerging applications.
格林伯格-霍恩-泽林格（GHZ）态，也被称为双分量薛定谔猫态，在量子物理基础和潜在量子应用中发挥着至关重要的作用。GHZ态的规模扩大及其相干控制对于在具有实际优势的先进计算任务中利用纠缠都至关重要，然而遗憾的是，由于GHZ态易受噪声影响，这带来了巨大挑战。在此，我们提出一种用于创建、保存和操纵大规模GHZ纠缠的通用策略，并展示了一系列以高保真数字量子电路为基础的实验。在初始化方面，我们采用一种可扩展协议来创建多达60个量子比特的真正纠缠的GHZ态，几乎使之前的规模记录翻倍。在保护方面，我们从离散时间晶体（DTC）的不同角度出发，DTC最初用于探索奇异的非平衡量子物质，我们将一个GHZ态嵌入到一个特制的猫态伤疤DTC的本征态中以延长其寿命。在操纵方面，我们使用原位量子门切换DTC本征态以改变GHZ保护的有效性。我们的研究结果为大规模纠缠的相干操作开辟了一条可行之路，并进一步凸显超导处理器是探索非平衡量子物质和新兴应用的一个有前景的平台。
