Optimized Source Placement for Multipartite State Distribution in Quantum Networks

The evolution of quantum networks towards distributed quantum computing and sensing necessitates the efficient distribution of multipartite entangled states among multiple users. However, most existing entanglement routing studies primarily focus on efficient entanglement distribution and typically assume that quantum sources are either fixed or available on all network edges. Due to the scarcity and high cost of quantum sources, some prior studies have focused on optimized source placement strategies, but these existing studies are confined to bipartite state distributions. Consequently, how to jointly optimize quantum source placement and entanglement routing for efficient multipartite state distribution under realistic resource constraints remains an open problem. In this work, we propose an Optimized source Placement and Reactive entanglement Routing (OP-RR) framework to maximize the multipartite state distribution rate given a limited amount of quantum sources. Numerical results on a grid and on the Tokyo topology demonstrate that OP-RR consistently outperforms baseline algorithms with non-optimized source placement, achieving an improvement of up to 16.7× in the multipartite distribution rate, while maintaining robustness under varying operation probabilities and scalability as the size of multipartite states increases.