A proposal for practical multidimensional quantum networks

TL;DR

This paper proposes a practical design for high-dimensional quantum networks using standard optical resources, simplifying implementation and enhancing noise robustness, thus advancing the development of a global quantum internet.

Contribution

It introduces a feasible entanglement swapping scheme for qudits using linear optics and standard resources, enabling practical high-dimensional quantum networks.

Findings

Optimized secret key rates through network parameter tuning.

Demonstrated enhanced noise robustness at higher dimensions.

Simplified implementation with current optical technology.

Abstract

A Quantum Internet, i.e., a global interconnection of quantum devices, is the long term goal of quantum communications, and has so far been based on two-dimensional systems (qubits). Recent years have seen a significant development of high-dimensional quantum systems (qudits). While qudits present higher photon information efficiency and robustness to noise, their use in quantum networks present experimental challenges due to the impractical resources required in high-dimensional quantum repeaters. Here, we show that such challenges can be met via the use of standard quantum optical resources, such as weak coherent states or weak squeezed states, and linear optics. We report a concrete design and simulations of an entanglement swapping scheme for three and four dimensional systems, showing how the network parameters can be tuned to optimize secret key rates and analysing the enhanced noise robustness at different dimensions. Our work significantly simplifies the implementation of high-dimensional quantum networks, fostering their development with current technology.