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.