Concurrent Entanglement Routing for Quantum Networks

TLDR

Quantum entanglement underpins quantum key distribution and long‑distance secret sharing, but multi‑hop entanglement suffers high failure rates and current networks rely on trusted repeaters, making end‑to‑end entanglement without revealing secrets a challenge as networks scale. The study aims to solve the entanglement routing problem by constructing long‑distance entanglements through untrusted repeaters for multiple concurrent source‑destination pairs. To address this, the authors develop a comprehensive entanglement routing model that captures quantum‑specific characteristics and propose the Q‑CAST algorithm that exploits these properties. Evaluation demonstrates that Q‑CAST significantly boosts the success rate of long‑distance entanglements over existing methods, and the accompanying model and simulator provide a platform for further research.

Abstract

Quantum entanglement enables important computing applications such as quantum key distribution. Based on quantum entanglement, quantum networks are built to provide long-distance secret sharing between two remote communication parties. Establishing a multi-hop quantum entanglement exhibits a high failure rate, and existing quantum networks rely on trusted repeater nodes to transmit quantum bits. However, when the scale of a quantum network increases, it requires end-to-end multi-hop quantum entanglements in order to deliver secret bits without letting the repeaters know the secret bits. This work focuses on the entanglement routing problem, whose objective is to build long-distance entanglements via untrusted repeaters for concurrent source-destination pairs through multiple hops. Different from existing work that analyzes the traditional routing techniques on special network topologies, we present a comprehensive entanglement routing model that reflects the differences between quantum networks and classical networks as well as a new entanglement routing algorithm that utilizes the unique properties of quantum networks. Evaluation results show that the proposed algorithm Q-CAST increases the number of successful long-distance entanglements by a big margin compared to other methods. The model and simulator developed by this work may encourage more network researchers to study the entanglement routing problem.