Multipartite multiplexing strategies for quantum routers

TL;DR

This paper investigates multipartite quantum routing strategies, extending bipartite multiplexing concepts to N-party networks, and analyzes how multiplexing improves secret key rates in quantum communication.

Contribution

It introduces a general protocol for N-party quantum networks with multiplexing, extending previous bipartite models, and optimizes secret key rates through strategic qubit selection.

Findings

Multiplexing significantly increases router rates in N-party quantum networks.

Optimal secret key rates are achieved by using cutoffs and selecting qubits with fewer storage rounds.

Explicit results demonstrate improvements in tripartite network secret key rates.

Abstract

This work explores the important role of quantum routers in communication networks and investigates the increase in efficiency using memories and multiplexing strategies. Motivated by the bipartite setup introduced by Abruzzo et al. (2013) for finite-range multiplexing in quantum repeaters, we extend the study to an N-partite network with a router as a central station. We present a general protocol for N parties after defining the underlying matching problem and we calculate the router rate for different N. We analyze the improvement due to multiplexing, and analyze the secret key rate with explicit results for the tripartite network. Investigating strategic qubit selection for the GHZ measurements, we show that using cutoffs to remove qubits after a certain number of rounds and consistently combining qubits with the lowest number of storage rounds leads to an optimal secret key rate.