Fidelity-Age-Aware Scheduling in Quantum Repeater Networks

2026-02-10

AI Summary

This work addresses the challenge of effectively measuring and scheduling entanglement distribution freshness—defined as the time elapsed since the last successful delivery—in quantum repeater networks, where fidelity, latency, and resource contention must be jointly optimized. The authors propose a novel Fidelity-Age (FA) metric that integrates physically interpretable freshness with fidelity thresholds. They develop a renewal-process-based analytical model for the long-term average FA and design a lightweight scheduler under resource constraints to minimize FA. Leveraging stochastic control theory and Lyapunov drift optimization, they derive low-complexity, real-time policies—FA-THR and FA-INDEX. Simulations demonstrate that the proposed approach reduces extreme high-age events by up to two orders of magnitude while maintaining throughput, significantly enhancing the timeliness and reliability of entanglement distribution.

Technology Category

• Planning, Routing, and Scheduling: Scheduling under Uncertainty
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Distributed Search

Application Category

• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics
• Security and Privacy: Large-scale security measurements
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Quantum repeater networks distribute entanglement over long distances but must balance fidelity, delay, and resource contention. Prior work optimized throughput and end-to-end fidelity, yet little attention has been paid to the freshness of entanglement-the time since a usable Bell pair was last delivered. We introduce the Fidelity-Age (FA) metric, which measures this interval for states whose fidelity exceeds a threshold Fmin. A renewal formulation links slot-level success probability to long-run average FA, enabling a stochastic control problem that minimizes FA under budget and memory limits. Two lightweight schedulers, FA-THR and FA-INDEX, approximate Lyapunov-drift-optimal control. Simulations on slotted repeater grids show that FA-aware scheduling preserves throughput while reducing extreme-age events by up to two orders of magnitude. Fidelity-Age thus provides a tractable, physically grounded metric for reliable and timely entanglement delivery in quantum networks.

Problem

• Fidelity-Age
• Quantum Repeater Networks
• Entanglement Freshness
• Bell Pair
• Stochastic Control

Innovation

• Fidelity-Age
• quantum repeater networks
• entanglement freshness
• stochastic control
• Lyapunov drift