Making Quantum Networks Work: Routing, Calibration, and Programmable Quantum Repeaters

2026-06-20

AI Summary

Quantum networks face fundamental challenges due to the no-cloning theorem, the stochastic nature of entanglement generation, decoherence, and hardware drift, rendering conventional network abstractions inadequate. To address these constraints in practical quantum repeater networks, this work proposes a gray-box routing approach that reduces reliance on global network state information, introduces a scheduling model that decouples calibration from operational tasks, and develops a programmable instruction set architecture for nitrogen-vacancy (NV) center–based repeater nodes. By integrating heterogeneous routing optimization, calibration-aware modeling, and a greedy orchestration heuristic, the proposed framework significantly lowers path blocking probability while enhancing network throughput and scalability, all without compromising end-to-end entanglement fidelity or fairness.

Abstract

The quantum internet enables distribution of quantum states across distant nodes, supporting secure communication, distributed computing, and quantum sensing. Unlike classical networks, it is constrained by the no cloning theorem, probabilistic entanglement generation, decoherence, and hardware drift, making classical abstractions inadequate. Scalable quantum networking therefore requires new architectures, protocols, and optimisation methods that explicitly account for these limitations. This thesis studies the architecture, routing, and operation of quantum networks under realistic constraints, focusing on bipartite entanglement distribution over quantum repeater networks. Key metrics include end to end fidelity, throughput, scalability, and fairness. At the network layer, routing strategies are developed beyond assumptions of homogeneous nodes and full network knowledge. Routing under heterogeneous repeater efficiencies shows how partial knowledge of node quality improves fidelity and reduces path blocking. A grey box routing approach is then introduced, where path selection relies only on topology and end to end estimates, achieving robustness and fairness without detailed link information. At the link layer, calibration and hardware drift are addressed through a calibration aware model separating activation and calibration phases. For linear repeater chains, an optimal calibration schedule is derived to balance operation time and calibration overhead. This is extended to general topologies with shared links, where a greedy orchestration heuristic is proposed. Finally, the thesis connects network protocols with hardware via an instruction set architecture for programmable quantum repeater nodes based on NV centers, enabling coherent programmability and linking physical operations to higher layer protocols.

Problem

• quantum networks
• entanglement distribution
• quantum repeaters
• hardware drift
• scalability

Innovation

• quantum repeaters
• routing
• calibration
• programmable architecture
• NV centers