Resource-Effcient Quantum Beneš Networks

Abstract

Distributing quantum states and entanglement between multiple pairs of nodes is a fundamental task in quantum communication and distributed quantum computing on large-scale quantum networks. In particular, the simultaneous distribution of quantum states or entanglement among multiple source-destination pairs (quantum k -pair communication task) is an emerging demand for scalable quantum networks. Here, we propose a quantum network architecture based on the Beneš switching topology that provides a universal switching framework for such pairwise communications. Our network architecture requires only O ( k log k ) pre-established entangled resources to accomplish the k -pair communication task, and offers advantages of non-blocking and low latency. We develop routing protocols for concurrent entanglement distribution and analyze their performance under ideal operating assumptions, while also discussing the effects of nonideal entanglement generation, quantum memory decoherence, photon loss, and finite Bell state measurement (BSM) success probability. The proposed framework requires local BSMs and entanglement swapping operations and is compatible in principle with quantum platforms supporting these capabilities. In particular, photonic implementations can benefit from mature photonic components and be compatible with existing telecommunications infrastructure.