Satellite-Aided Entanglement Distribution for Optimized Quantum Networks

Abstract: Quantum internet needs to ensure timely provision of entangled qubits to be used in tasks that involve distributed quantum computing or sensing. This has been addressed by a top-down approach of optimized quantum networks [arXiv:2107.10275], in which entanglement is distributed prior to receiving tasks. Upon the task arrival, the desired entanglement state is attained with local operations and classical communication. The pre-distribution of entanglements should aim to minimize the amount of qubits used, as this decreases the risk of decoherence and thus degradation of the entangled state. The optimized quantum networks consider a multi-hop optical network and in this work we are supplementing it with Satellite-aided Entanglement Distribution (SED). The motivation is that satellites can shortcut the topology and place the entanglement at two nodes not directly connected through the optical network. We devise an algorithm for strategic placement of entanglements with SED, which results in a decrease in the number of qubits used in pre-distribution of entanglement. The numerical results show that SED can significantly enhance the performance of small quantum networks, while Entanglement-sharing Constraints (EC) are critical for large networks.