Entanglement Management Through Swapping Over Quantum Internets

Quantum Internet has the potential to support a wide range of applications in quantum communication and quantum computing by generating, distributing, and processing quantum information. Generating a long-distance quantum entanglement is one of the most fundamental functions of a quantum Internet to facilitate these applications. However, entanglement is a probabilistic process, and its success rate drops significantly as distance increases. Entanglement-swapping is an efficient technique used to address this challenge. How to efficiently manage the entanglement through swapping is a fundamental yet challenging problem. This article considers two entanglement-swapping methods: (1) Bell state measurement (BSM) entanglement-swapping: a classic entanglement-swapping method that is able to fuse two successful quantum links, (2) Greenberger-Horne-Zeilinger (GHZ) measurement entanglement-swapping: a more general and efficient swapping method which is capable of fusing $n$ successful quantum links. The goal is to maximize the entanglement rate for multiple quantum processor unit (QPU) pairs over the quantum Internet with a general topology. Two efficient entanglement management protocols are proposed which respectively make use of the unique properties of BSM and GHZ. Evaluation results highlight that the proposed protocols outperform the existing ones.