Entanglement-Based Crossbar for Quantum Routers

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.