A three-node quantum network in The Netherlands:
Future quantum networks will provide the means to develop truly secure communication channels and will have applications in many other quantum-based technologies. Pompili et al. present a three-node remote quantum network based on solid-state spin qubits (nitrogen-vacancy centers in diamond) coupled by photons. The implementation of two quantum protocols on the network. entanglement distribution and entanglement swapping, illustrates a key platform for exploring, testing, and developing multinode quantum networks and quantum protocols.
The distribution of entangled states across the nodes of a future quantum internet will unlock fundamentally new technologies. Here, we report on the realization of a three-node entanglement-based quantum network. We combine remote quantum nodes based on diamond communication qubits into a scalable phase-stabilized architecture, supplemented with a robust memory qubit and local quantum logic. In addition, we achieve real-time communication and feed-forward gate operations across the network. We demonstrate two quantum network protocols without postselection: the distribution of genuine multipartite entangled states across the three nodes and entanglement swapping through an intermediary node. Our work establishes a key platform for exploring, testing, and developing multinode quantum network protocols and a quantum network control stack.
M. Pompili, S. L. N. Hermans, S. Baier, H. K. C. Beukers, P. C. Humphreys, R. N. Schouten, R. F. L. Vermeulen, M. J. Tiggelman, L. dos Santos Martins, B. Dirkse, S. Wehner, R. HansonQuTech, Delft University of Technology, 2628 CJ Delft, Netherlands; Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands; Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria; DeepMind, London, UK; QBlox, 2628 CJ Delft, Netherlands.