Quantum Entanglement Allocation through a Central Hub

TL;DR

This paper introduces resource-efficient LOCC protocols for distributing multipartite entangled states, specifically W and GHZ states, in a centralized quantum network architecture, improving over traditional teleportation methods.

Contribution

It presents the first optimal LOCC protocols for allocating generalized N-qubit W states in a centralized hub, reducing resource costs compared to existing methods.

Findings

Deterministic and exact distribution of states with N qubits of memory.

Communication costs of 2N - 2 and N classical bits for W and GHZ states.

Protocols outperform conventional teleportation in resource efficiency.

Abstract

Establishing a fully functional quantum internet relies on the efficient allocation of multipartite entangled states, which enables advanced quantum communication protocols, secure multipartite quantum key distribution, and distributed quantum computing. In this work, we propose local operations and classical communication (LOCC) protocols for allocating generalized $N$-qubit W states within a centralized hub architecture, where the central hub node preshares Bell states with each end node. We develop a detailed analysis of the optimality of the resources required for our proposed W-state allocation protocol and the previously proposed GHZ-state protocol. Our results show that these protocols deterministically and exactly distribute states using only $N$ qubits of quantum memory within the central system, with communication costs of $2N - 2$ and $N$ classical bits for the W and GHZ states, respectively. These resource-efficient LOCC protocols are further proven to be optimal within the centralized hub architecture, outperforming conventional teleportation protocols for entanglement distribution in both memory and communication costs. Our results provide a more resource-efficient method for allocating essential multipartite entangled states in quantum networks, paving the way for the realization of a quantum internet with enhanced efficiency.