Classical crossbar routers cannot be directly adopted in the quantum domain, due to the laws of quantum mechanics. In this paper, we propose an \textit{entanglement-based crossbar} as the quantum counterpart of the classical switching fabric, enabling generalized forwarding solely through local Pauli measurements on a multipartite entangled resource, acting as a switching fabric. We formalize the notions of blocking and non-blocking conditions in the quantum domain by providing the design tenets to achieve a non-blocking switching fabric. Then, we introduce the edge-controlled design principle by identifying the minimal 2x2 non-blocking base unit as the fundamental building block for scalable router architectures. The proposed framework provides a hardware-agnostic and scalable foundation for quantum routers, bridging classical network theory with quantum-native forwarding.Classical crossbar routers cannot be directly adopted in the quantum domain, due to the laws of quantum mechanics. In this paper, we propose an \textit{entanglement-based crossbar} as the quantum counterpart of the classical switching fabric, enabling generalized forwarding solely through local Pauli measurements on a multipartite entangled resource, acting as a switching fabric. We formalize the notions of blocking and non-blocking conditions in the quantum domain by providing the design tenets to achieve a non-blocking switching fabric. Then, we introduce the edge-controlled design principle by identifying the minimal 2x2 non-blocking base unit as the fundamental building block for scalable router architectures. The proposed framework provides a hardware-agnostic and scalable foundation for quantum routers, bridging classical network theory with quantum-native forwarding.

Jan 18, 20260 citations

The Future Quantum Internet

Fabio Cavaliere, Rana Pratap Sircar, Tommaso Catuogno

Springer eBooksJan 1, 20222 citations

Experimental demonstration of an entanglement-based quantum router

X.-Y. Chang, Y. X. Wang, Chong Zu +2 more

We report an experiment that demonstrates full function of a quantum router using entangled photons, where the paths of a single-photon pulse are controlled in a coherent fashion by polarization of another single photon. Through a projective measurement, we prepare the polarization of the control photon in arbitrary superposition states, leading to coherent routing of the target photon in quantum superposition of different paths. We demonstrate quantum nature of this router through optical measurements based on quantum state tomography and show an average fidelity of $(93.24\pm 0.23)%$ for the quantum routing operation.We report an experiment that demonstrates full function of a quantum router using entangled photons, where the paths of a single-photon pulse are controlled in a coherent fashion by polarization of another single photon. Through a projective measurement, we prepare the polarization of the control photon in arbitrary superposition states, leading to coherent routing of the target photon in quantum superposition of different paths. We demonstrate quantum nature of this router through optical measurements based on quantum state tomography and show an average fidelity of $(93.24\pm 0.23)%$ for the quantum routing operation.

arXiv:1207.7265Jul 31, 20126 citations

Towards a Blueprint for a Quantum Internet

Stephanie Wehner

Bulletin of the American Physical SocietyMar 16, 20210 citations

On Matching in Multipartite Quantum Routers

Dagmar Bruß, Luis Gindorf, Julia Kunzelmann +2 more

Over the past few years, the concept of quantum routers and their usefulness in quantum communication networks (e.g., in the BB84 protocol [5]) has been popularized in quantum information theory. While quite some work has been done on the theoretical implementation of quantum routers using multiplexing, most of it is constrained to the bipartite case [2, 9]. We extend this setup to quantum routers used in multipartite conference key agreement protocols so as to distribute a secret key among N parties. We formalize the general quantum entanglement matching problem, and show it's NP-completeness. We then study special cases for which we found efficient algorithms. Finally, we consider the weighted case where the weights represent the qubit ages.Over the past few years, the concept of quantum routers and their usefulness in quantum communication networks (e.g., in the BB84 protocol [5]) has been popularized in quantum information theory. While quite some work has been done on the theoretical implementation of quantum routers using multiplexing, most of it is constrained to the bipartite case [2, 9]. We extend this setup to quantum routers used in multipartite conference key agreement protocols so as to distribute a secret key among N parties. We formalize the general quantum entanglement matching problem, and show it's NP-completeness. We then study special cases for which we found efficient algorithms. Finally, we consider the weighted case where the weights represent the qubit ages.

ACM International Symposium on High-Performance Parallel and Distributed Computing (HPDC)Jul 20, 20250 citations

(93.24\pm 0.23)%

for the quantum routing operation.