An efficient Progressive Swapping to the Middle distribution protocol adapted to imperfect quantum memories in quantum networks
This work addresses the problem of efficient entanglement distribution for quantum networks, which is crucial for enabling long-distance quantum communication.
This paper introduces Progressive Swapping to the Middle (PSM), a new entanglement distribution protocol for quantum networks that combines existing Progressive Swapping from both ends of a path. PSM achieves a significantly better link probability than Progressive Swapping while maintaining reasonable link fidelity and demonstrating resource consumption advantages over other protocols.
The distribution of entangled pairs of photons on the links composing a quantum network, combined with Bell state measurements and teleportation, is the basic apparatus to transfer quantum bits (qubits) over long distances. Entanglement distribution establishes an end-to-end entangled pair while consuming intermediate pairs on links and holding them for a certain time period. The technical literature identifies two main kinds of protocols, parallel and sequential ones, the latter having an advantage in resource consumption over the former. In this paper, we introduce an efficient swapping protocol called Progressive Swapping to the Middle (PSM) as it combines the existing Progressive Swapping (PS) protocol from both extremities of a path that meet in the middle where the received pairs are swapped. We compare PSM with two parallel protocols and PS; in our evaluation, we take into account imperfect memories and fidelity degradation. We demonstrate that PSM yields a much better link probability than PS while keeping a reasonable link fidelity, and shows an advantage in resource consumption over other protocols.