Realization of a multi-node quantum network using diamond spin qubits: Part I – Enabling technologies

A future quantum internet can unlock fundamentally new technologies by sharing entangled states across the nodes of the network. In the past decade, many buildings blocks of such a network have been demonstrated. In particular, the heralded distribution of entanglement between two physically separated nodes has been achieved on various platforms. Here we report on the experimental realization of a multi-node quantum network. Our network consists of three quantum nodes with Nitrogen Vacancy (NV) electron spins as communication qubits. Additionally, the middle node makes use of a nuclear spin qubit that serves as a quantum memory.
In this presentation we discuss the key technological advancements that have enabled the realization of the quantum network: a scalable architecture for the stabilization of the phase of the entangled states of a single link; an improvement of the quantum memory lifetime under network activity; real-time communication and feedback gates across the network.
Our work serves as a proof of principle demonstration of a quantum network and enables the exploration of the first multi-node protocols.