Multi-User Entanglement Distribution in Quantum Networks Using Multipath Routing

Abstract: Quantum networks facilitate numerous applications such as secure communication and distributed quantum computation by performing entanglement distribution. Multi-user quantum applications where quantum information is shared between multiple users require access to a shared multipartite state between the users. We consider the problem of designing protocols for distributing such states, at an increased entanglement rate. We propose three protocols that increase the entanglement rate of multi-user applications by leveraging multipath routing. The protocols are evaluated on quantum networks with NISQ constraints, including limited quantum memories and probabilistic entanglement generation. Monte Carlo simulation results show that the developed protocols achieve an exponential speedup of entanglement rate compared to single-path routing techniques, with a maximum speedup of four orders of magnitude for the cases studied. The speedup was also found to improve for larger sets of users. When the protocols were tested in scaled-down real-world topologies, it was found that topology can have a significant effect on the achievable entanglement rates, with one order of magnitude difference between topologies. Finally, we find that the benefits of multipath routing are a maximum for short quantum memory decoherence times, and intermediate values of entanglement generation probability. Hence the protocols developed can benefit NISQ quantum network control and design.