Wang Meihong, Xiang Yu, Kang Haijun, Han Dongmei, Liu Yang, He Qiongyi, Gong Qihuang, Su Xiaolong, Peng Kunchi
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
Phys Rev Lett. 2020 Dec 31;125(26):260506. doi: 10.1103/PhysRevLett.125.260506.
As two valuable quantum resources, Einstein-Podolsky-Rosen entanglement and steering play important roles in quantum-enhanced communication protocols. Distributing such quantum resources among multiple remote users in a network is a crucial precondition underlying various quantum tasks. We experimentally demonstrate the deterministic distribution of two- and three-mode Gaussian entanglement and steering by transmitting separable states in a network consisting of a quantum server and multiple users. In our experiment, entangled states are not prepared solely by the quantum server, but are created among independent users during the distribution process. More specifically, the quantum server prepares separable squeezed states and applies classical displacements on them before spreading out, and users simply perform local beam-splitter operations and homodyne measurements after they receive separable states. We show that the distributed Gaussian entanglement and steerability are robust against channel loss. Furthermore, one-way Gaussian steering is achieved among users that is useful for further directional or highly asymmetric quantum information processing.
作为两种宝贵的量子资源，爱因斯坦 - 波多尔斯基 - 罗森纠缠和导引在量子增强通信协议中发挥着重要作用。在网络中将此类量子资源分配给多个远程用户是各种量子任务的关键先决条件。我们通过在由量子服务器和多个用户组成的网络中传输可分离态，实验证明了双模和三模高斯纠缠与导引的确定性分配。在我们的实验中，纠缠态并非仅由量子服务器制备，而是在分配过程中由独立用户之间创建。更具体地说，量子服务器制备可分离的压缩态，并在其传播之前对其应用经典位移，用户在接收到可分离态后只需执行本地分束器操作和零差测量。我们表明，分布式高斯纠缠和导引性对信道损耗具有鲁棒性。此外，在用户之间实现了单向高斯导引，这对于进一步的定向或高度不对称量子信息处理是有用的。
