Park Geobae, Hofmann Holger F, Okamoto Ryo, Takeuchi Shigeki
Department of Electronic Science and Engineering, Kyoto University, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi Hiroshima 739-8530, Japan.
Sci Adv. 2025 Sep 12;11(37):eadx4180. doi: 10.1126/sciadv.adx4180.
Entangled measurements are an indispensable tool for quantum information processing, such as Bell-state measurements in quantum teleportation and entanglement swapping. However, to date, the realization of entangled measurements has mainly focused on bipartite systems or Greenberger-Horne-Zeilinger (GHZ) states. Here, we demonstrate a practical scheme to realize entangled measurements for [Formula: see text] states. Thanks to the cyclic shift symmetry in the discrete Fourier transformation (DFT) of bosonic modes, the DFT measurement outcomes can be used to deterministically project multiqubit states onto [Formula: see text] states. Experimentally, we show that three-qubit [Formula: see text] state discrimination can be achieved by detecting the cyclic shift symmetry with a three-mode DFT optical circuit, yielding a measurement discrimination fidelity of 0.871 ± 0.039. Our experimental demonstration opens the door for the development of new quantum network protocols between multipartite systems.
纠缠测量是量子信息处理中不可或缺的工具，例如量子隐形传态和纠缠交换中的贝尔态测量。然而，迄今为止，纠缠测量的实现主要集中在两体系统或格林伯格 - 霍恩 - 泽林格（GHZ）态上。在此，我们展示了一种实现对[公式：见原文]态进行纠缠测量的实用方案。由于玻色子模式的离散傅里叶变换（DFT）中的循环移位对称性，DFT测量结果可用于将多量子比特态确定性地投影到[公式：见原文]态上。在实验中，我们表明通过使用三模DFT光学电路检测循环移位对称性，可以实现三量子比特[公式：见原文]态的区分，测量区分保真度为0.871±0.039。我们的实验演示为多体系统之间新的量子网络协议的发展打开了大门。
