Bridging All-Photonic and Memory-Based Quantum Repeaters

The all-photonic quantum repeater scheme based on repeater graph states (RGS) offers a promising approach for constructing quantum networks without relying on long-coherence-time quantum memories, which remain a significant technological challenge. Despite substantial progress in defining new schemes for generating RGSs, and in analyzing their performance for the task of secret key generation, the integration of all-photonic schemes with memory-equipped quantum repeaters remains underexplored. We propose an architecture that enables seamless interoperability between all-photonic and memory-based quantum repeaters through an emitter-photon qubit building block, significantly reducing the number of quantum memories required at end nodes from a multiplicative dependence on the trial rate and number of RGS arms to an additive scaling. The core idea of our architecture is to abstract the all-photonic sections of the network as link-level connections between memory-equipped nodes, enabling integration into existing network-level protocols. Additionally, we outline the content and semantics of the messages necessary for a communication protocol based on graph state manipulation rules for computing Pauli frame corrections for obtaining the correct Bell pair. Our approach also provides a simplified method for calculating state fidelity directly from graph state properties.