Calculating the Capacity Region of a Quantum Switch

TL;DR

This paper introduces a convex analysis-based method to calculate the capacity region of quantum switches, supporting mixed entanglement, with example topologies and simulation validation.

Contribution

It presents a novel analytical approach for determining the capacity region of quantum switches supporting mixed entanglement, applicable to both discrete and continuous variables.

Findings

Method successfully calculates capacity boundaries for quantum switches.

Illustrative topologies demonstrate the method's applicability.

Simulations validate the analytical results.

Abstract

Quantum repeaters are necessary to fully realize the capabilities of the emerging quantum internet, especially applications involving distributing entanglement across long distances. A more general notion of this can be called a quantum switch, which connects to many users and can act as a repeater to create end-to-end entanglement between different subsets of these users. Here we present a method of calculating the capacity region of both discrete- and continuous-variable quantum switches that in general support mixed-partite entanglement generation. The method uses tools from convex analysis to generate the boundaries of the capacity region. We show example calculations with illustrative topologies and perform simulations to support the analytical results.