QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
Institut für Experimentalphysik, Universität Innsbruck, Innsbruck, Austria.
Nature. 2022 May;605(7911):663-668. doi: 10.1038/s41586-022-04697-y. Epub 2022 May 25.
Future quantum internet applications will derive their power from the ability to share quantum information across the network. Quantum teleportation allows for the reliable transfer of quantum information between distant nodes, even in the presence of highly lossy network connections. Although many experimental demonstrations have been performed on different quantum network platforms, moving beyond directly connected nodes has, so far, been hindered by the demanding requirements on the pre-shared remote entanglement, joint qubit readout and coherence times. Here we realize quantum teleportation between remote, non-neighbouring nodes in a quantum network. The network uses three optically connected nodes based on solid-state spin qubits. The teleporter is prepared by establishing remote entanglement on the two links, followed by entanglement swapping on the middle node and storage in a memory qubit. We demonstrate that, once successful preparation of the teleporter is heralded, arbitrary qubit states can be teleported with fidelity above the classical bound, even with unit efficiency. These results are enabled by key innovations in the qubit readout procedure, active memory qubit protection during entanglement generation and tailored heralding that reduces remote entanglement infidelities. Our work demonstrates a prime building block for future quantum networks and opens the door to exploring teleportation-based multi-node protocols and applications.
未来的量子互联网应用将得益于在网络中共享量子信息的能力。量子隐形传态允许在远距离节点之间可靠地传输量子信息，即使在高度损耗的网络连接中也是如此。尽管已经在不同的量子网络平台上进行了许多实验演示，但要超越直接连接的节点，仍然受到远程共享远程纠缠、联合量子位读取和相干时间等苛刻要求的限制。在这里，我们在量子网络中的远程非相邻节点之间实现了量子隐形传态。该网络使用三个基于固态自旋量子位的光连接节点。通过在两个链路之间建立远程纠缠，然后在中间节点上进行纠缠交换，并在存储量子位中存储，来准备隐形传态。我们证明，一旦成功地对隐形传态进行了标记，就可以以高于经典界限的保真度传送任意量子位状态，甚至效率为 1。这些结果得益于在量子位读取过程中的关键创新、在纠缠产生过程中对存储量子位的主动保护以及减少远程纠缠失效率的定制标记。我们的工作展示了未来量子网络的主要构建模块，并为探索基于隐形传态的多节点协议和应用开辟了道路。
