Distributing Multipartite Entanglement over Noisy Quantum Networks

A quantum internet aims at harnessing networked quantum technologies, namely by distributing bipartite entanglement be-tween distant nodes. However, multipar-tite entanglement between the nodes may empower the quantum internet for addi-tional or better applications for commu-nications, sensing, and computation. In this work, we present an algorithm for generating multipartite entanglement be-tween different nodes of a quantum net-work with noisy quantum repeaters and imperfect quantum memories, where the links are entangled pairs. Our algorithm is optimal for GHZ states with 3 qubits, maximising simultaneously the final state fidelity and the rate of entanglement dis-tribution. Furthermore, we determine the conditions yielding this simultaneous opti-mality for GHZ states with a higher num-ber of qubits, and for other types of mul-tipartite entanglement. Our algorithm is general also in the sense that it can op-timize simultaneously arbitrary parame-ters. This work opens the way to opti-mally generate multipartite quantum cor-relations over noisy quantum networks, an important resource for distributed quan-tum technologies.