近日，上海交通大学陈贤峰团队研究了基于时间纠缠的频率转换和贝尔态测量的多用户量子通信网络。相关论文于2025年5月12日发表在《物理评论A》杂志上。

大规模量子通信系统通常需要通过频率转换将不同的信道连接到多个网络，这需要频率转换器作为系统连接的中继点。研究组提出了一种基于时间纠缠的单光子频率转换量子网络，合法用户可以通过独立选择目标转换频率模式来实现用户之间通信频带的跨越。 

结果表明，网络中的转换器可以通过级联二次非线性过程，作为完全连接两个网络的桥梁。同时，转换后的量子纠缠态在纠缠测量中得到了证明，可用于纠缠交换。该方案有望广泛应用于不同网络共享量子资源、交换通信信道和有效连接不同多路复用频谱的场景。这一概念也在大规模城域网中提供了重要的应用。

附：英文原文

Title: Multiuser quantum communication network via time-bin-entanglement-based frequency conversion and Bell-state measurement

Author: Zhantong Qi, Yilin Yang, Chennan Wu, Zixuan Liao, Bo Tang, Jiani Lei, Yuanhua Li, Jia Lin, Yuanlin Zheng, Xianfeng Chen

Issue&Volume: 2025/05/12

Abstract: Large-scale quantum communication systems often require different channels to be connected to multiple networks via frequency conversion, which requires frequency converters to act as relay points for system connectivity. We propose a quantum network for single-photon frequency conversion based on time-bin entanglement, where legitimate users can realize the spanning of communication bands between users by independently choosing the target conversion frequency mode. The results show that the converter in the network can be used as a bridge to completely connect the two networks by cascading the quadratic nonlinear process. Meanwhile, the converted quantum entangled states are demonstrated in entanglement measurements and can be used for entanglement swapping. This scheme is expected to be widely used in scenarios where different networks share quantum resources, switching communication channels and effectively connecting different multiplexed spectrum. This concept also provides significant applications in large-scale metropolitan area networks.

DOI: 10.1103/PhysRevA.111.052609

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.111.052609