HOPPER: A Hop-by-hop Entanglement Distribution Protocol for Asynchronous Quantum Networks

2026-05-15

AI Summary

Existing quantum networks predominantly rely on serial operations for entanglement distribution, which fails to exploit the multi-quantum-memory capacity of intermediate nodes and consequently suffers from low efficiency over long distances. This work proposes HOPPER, an asynchronous entanglement distribution mechanism that enables concurrent reuse of entanglement requests. HOPPER introduces, for the first time in asynchronous quantum networks, a hop-by-hop autonomous resource scheduling strategy that allows intermediate nodes to process multiple entanglement requests in parallel. By breaking away from conventional serial constraints, the proposed approach significantly enhances both the throughput and resource utilization of end-to-end entanglement establishment. Extensive simulations demonstrate that HOPPER consistently outperforms existing synchronous schemes across diverse network scenarios.

Abstract

The quantum Internet relies on the ability to distribute entangled quantum bits (ebits) between quantum memories at the end nodes, to perform applications like blind or distributed quantum computing that are impossible if end nodes are connected via a classical, i.e., non-quantum network. This need creates new challenges due to the fragile nature of entanglement, which decoheres over short timescales and cannot be amplified, buffered, or retransmitted. Two broad categories of approaches have been proposed in the scientific literature to realize such an entanglement distribution in a given path: one relying on a synchronous time-slotted model, and another one where intermediate nodes interact asynchronously. However, both of them implicitly assume a serial operation, where one ebit is established and made available to the application on end nodes before creating a new one. This is inefficient in long-range networks, with high transmission latencies, if the intermediate nodes have multiple memory qubits that could be used in parallel. To overcome this limitation, in this paper, we study the implications of multiplexing concurrent ebit requests on the same quantum, for both synchronous and asynchronous operation. Furthermore, for the latter, we define a novel distribution protocol, called HOPPER, where the intermediate nodes make autonomous and hop-by-hop decisions on the use of their local resources when establishing an ebit. With numerical simulations, we show that HOPPER is effective in handling multiple ebit requests in parallel, and it exhibits significantly better performance than a synchronous alternative in different scenarios.

Problem

• entanglement distribution
• quantum networks
• asynchronous operation
• multiplexing
• quantum memory

Innovation

• entanglement distribution
• asynchronous quantum networks
• hop-by-hop protocol
• quantum memory multiplexing
• HOPPER