Distributing Multipartite Entanglement over Noisy Quantum Networks

TLDR

A quantum internet seeks to distribute entanglement across nodes, and multipartite entanglement could enhance communication, sensing, and computation. The study proposes an algorithm to generate multipartite entanglement across noisy quantum networks using entangled pair links. The algorithm optimizes GHZ state fidelity and distribution rate, and the authors identify conditions for optimality for larger GHZ states and other multipartite entanglement types. The algorithm achieves optimal fidelity and distribution rate for 3‑qubit GHZ states, can simultaneously optimize arbitrary parameters, and paves the way for efficient multipartite entanglement generation in noisy networks.

Abstract

A quantum internet aims at harnessing networked quantum technologies, namely by distributing bipartite entanglement between distant nodes. However, multipartite entanglement between the nodes may empower the quantum internet for additional or better applications for communications, sensing, and computation. In this work, we present an algorithm for generating multipartite entanglement between different nodes of a quantum network 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 distribution. Furthermore, we determine the conditions yielding this simultaneous optimality for GHZ states with a higher number of qubits, and for other types of multipartite entanglement. Our algorithm is general also in the sense that it can optimise simultaneously arbitrary parameters. This work opens the way to optimally generate multipartite quantum correlations over noisy quantum networks, an important resource for distributed quantum technologies.