Entanglement of spin waves among four quantum memories
Entanglement of spin waves among four quantum memories
复制标题
DOI：
10.1038/nature09568
复制
发表时间：
2010-11-18
期刊：
影响因子：
64.8
通讯作者：
Kimble, H. J.
中科院分区：
文献类型：
--
作者：
Choi, K. S.;Goban, A.;Kimble, H. J.
量子网络由量子节点组成，这些节点通过量子信道进行相干交互，并开辟了科学机会的广阔前沿。例如，量子网络可以作为连接量子处理器进行计算（2，3）和通信（4）的“网络”，或者作为“模拟器”，允许研究由通道（5，6）介导的节点之间的相互作用引起的量子临界现象。量子网络的物理实现通常需要能够在多个量子存储器中生成和存储纠缠态的动力学系统，并将存储的纠缠有效地传输到量子信道中，以便在网络中分发。虽然这种能力已经在不同的二分系统中得到了证明（7-12），但对于能够将存储在量子存储器中的多分纠缠“映射”到量子信道的互连，还没有实现纠缠态。在这里，我们展示了存储在四个原子存储器中的测量引起的纠缠;用户控制的，原子纠缠到四个光子通道的相干转移;以及使用量子不确定性关系表征完整的四方纠缠（13-16）。因此，我们的工作构成了量子网络中多体纠缠分布的进步。我们还表明，我们的纠缠验证方法适用于研究热平衡下凝聚态系统的纠缠阶数（17，18）。
Quantum networks are composed of quantum nodes that interact coherently through quantum channels, and open a broad frontier of scientific opportunities(1). For example, a quantum network can serve as a 'web' for connecting quantum processors for computation(2,3) and communication(4), or as a 'simulator' allowing investigations of quantum critical phenomena arising from interactions among the nodes mediated by the channels(5,6). The physical realization of quantum networks generically requires dynamical systems capable of generating and storing entangled states among multiple quantum memories, and efficiently transferring stored entanglement into quantum channels for distribution across the network. Although such capabilities have been demonstrated for diverse bipartite systems(7-12), entangled states have not been achieved for interconnects capable of 'mapping' multipartite entanglement stored in quantum memories to quantum channels. Here we demonstrate measurement-induced entanglement stored in four atomic memories; user-controlled, coherent transfer of the atomic entanglement to four photonic channels; and characterization of the full quadripartite entanglement using quantum uncertainty relations(13-16). Our work therefore constitutes an advance in the distribution of multipartite entanglement across quantum networks. We also show that our entanglement verification method is suitable for studying the entanglement order of condensed-matter systems in thermal equilibrium(17,18).