Quantum Networks using Spins in Diamond

A future quantum internet will bring revolutionary opportunities. In a quantum internet, information will be represented using qubits. These qubits obey the rules of quantum mechanics. The possibilities to create superposition and entangled states, and to perform projective measurements give the quantum internet its unique strengths. A quantuminternet will enable fundamentally secure communication, quantumcomputations in the cloud with complete privacy and quantum enhanced sensing. But it is likely that many of its applications are still unknown. A full-scale quantum internet puts demanding requirements on the individual components. In the last decades single nodes and remote entanglement have been explored, but a small-scale prototype quantum network does not yet exist. In this thesis we go beyond single- or two-node experiments and realize the first multi-node quantum network using nitrogen-vacancy centers in diamond. The electron spin of this defect serves as the communication qubit and nearby 13C nuclear spins as memory qubits. We investigate the performance of the network and demonstratemultiple key network-primitive protocols. In addition, we further explore and improve the individual building blocks...