Quantum Routers: A Switching-Fabric Framework for Quantum-Native Forwarding

Jessica Illiano; Caterina De Risi; Angela Sara Cacciapuoti; Marcello Caleffi

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arXiv · 2606.17773

Quantum Routers: A Switching-Fabric Framework for Quantum-Native Forwarding

Jessica Illiano·Caterina De Risi·Angela Sara Cacciapuoti·Marcello Caleffi

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Abstract

Forwarding in quantum networks cannot be realized by directly transposing classical switching fabrics, since the no-cloning theorem and the quantum measurement postulate constrain the direct relay of quantum information while ruling out copy-based buffering and inspection. In this paper, we propose a switching-fabric framework for quantum routers based on multipartite entanglement. Specifically, we formalize the notion of an entanglement-based switching fabric, in which a graph state acts as the forwarding resource and entanglement forwarding is realized through local Pauli measurements. We translate the classical notions of blocking and non-blocking operation into structural conditions for entanglement-based fabrics, by deriving the \textit{edge-controlled (EC) design principle} for non-blocking operation. We instantiate this principle through a monolithic \textit{EC crossbar} and a modular Clos-type EC fabric, for which we characterize resource scaling and identify the regime where the modular design becomes more resource-efficient than the monolithic one. Finally, a forwarding-latency analysis establishes a fundamental distinction between matching-oblivious and matching-driven forwarding: the proposed EC fabrics realize all requested input-output entanglement links with constant forwarding depth under sufficient measurement parallelism, whereas matching-driven EPR-based fabrics exhibit latency that scales with the number of requested connections. The proposed framework provides a hardware-agnostic foundation for quantum-router switching fabrics.

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Jessica Illiano, Caterina De Risi, Angela Sara Cacciapuoti, Marcello Caleffi. 2026-06-16. Quantum Routers: A Switching-Fabric Framework for Quantum-Native Forwarding. https://arxiv.org/abs/2606.17773

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