Multiplexing scheme for simplified entanglement-based large-alphabet quantum key distribution

TL;DR

This paper introduces a practical quantum key distribution scheme that combines high-dimensional entanglement with a simple two-dimensional Bell test, enhancing secure key rates and security against attacks using current technology.

Contribution

It presents a novel multiplexing approach that simplifies security verification in high-dimensional quantum key distribution systems.

Findings

Scheme achieves high information capacity with simplified security checks.

Provides security against collective attacks.

Feasible with current quantum technologies.

Abstract

We propose a practical quantum cryptographic scheme which combines high information capacity, such as provided by high-dimensional quantum entanglement, with the simplicity of a two-dimensional Clauser-Horne-Shimony-Holt (CHSH) Bell test for security verification. By applying a state combining entanglement in a two-dimensional degree of freedom, such as photon polarization, with high-dimensional correlations in another degree of freedom, such as photon orbital angular momentum (OAM) or path, the scheme provides a considerably simplified route towards security verification in quantum key distribution (QKD) aimed at exploiting high-dimensional quantum systems for increased secure key rates. It also benefits from security against collective attacks and is feasible using currently available technologies.