On the Analysis of Quantum Repeater Chains with Sequential Swaps

TL;DR

This paper analyzes the performance of quantum repeater chains with sequential swaps, deriving formulas for entanglement fidelity considering hardware imperfections, and explores their impact on quantum communication metrics.

Contribution

It provides closed-form expressions for entanglement fidelity in quantum repeater chains, extending previous analyses to continuous request scenarios using quantum information and queuing theory.

Findings

Derived formulas for average entanglement fidelity considering decoherence and imperfections

Analyzed the impact of hardware parameters and distance on fidelity and secret key rate

Extended fidelity analysis to continuous request scenarios using combined theoretical approaches

Abstract

We evaluate the performance of two-way quantum repeater chains with sequential entanglement swapping. Within the analysis we consider memory decoherence, gate imperfections, and imperfect link-level entanglement generation. Our main results include closed-form expressions for the average entanglement fidelity of the generated end-to-end entangled states. We generalize previous findings for the one-shot fidelity analysis and study the case where repeater chains serve end-to-end requests continuously. We provide solutions to the continuous request scenario by combining results from quantum information theory and queuing theory. Finally, we apply the formulas obtained to analyze the impacts of hardware parameters, i.e., coherence times and gate fidelity, and distance on the entanglement fidelity and secret key rate of homogeneous quantum repeater chains.