Analysis of Multipartite Entanglement Distribution using a Central Quantum-Network Node

TL;DR

This paper analyzes the rate and fidelity of distributing multipartite GHZ entangled states in quantum networks via a central node, considering noise effects and comparing different distribution schemes.

Contribution

It provides analytical bounds for GHZ state distribution performance and compares centralized versus distributed entanglement creation methods.

Findings

Analytical expressions for rate and fidelity of GHZ state distribution.

Fidelity bounds account for time-dependent depolarizing noise.

Performance comparison between central node and distributed entanglement creation.

Abstract

We study the performance (rate and fidelity) of distributing multipartite entangled states in a quantum network through the use of a central node. Specifically, we consider the scenario where the multipartite entangled state is first prepared locally at a central node, and then transmitted to the end nodes of the network through quantum teleportation. As our first result, we present leading-order analytical expressions and lower bounds for both the rate and fidelity at which a specific class of multipartite entangled states, namely Greenberger-Horne-Zeilinger (GHZ) states, are distributed. Our analytical expressions for the fidelity accurately account for time-dependent depolarizing noise encountered by individual quantum bits while stored in quantum memory, as verified using Monte Carlo simulations. As our second result, we compare the performance to the case where the central node is an entanglement switch and the GHZ state is created by the end nodes in a distributed fashion. Apart from these two results, we outline how the teleportation-based scheme could be physically implemented using trapped ions or nitrogen-vacancy centers in diamond.