On High-Dimensional Twin-Field Quantum Key Distribution

TL;DR

This paper investigates the potential and limitations of extending Twin-Field Quantum Key Distribution to high-dimensional quantum states, highlighting that such generalizations are fundamentally constrained.

Contribution

It defines the core principles of Twin-Field QKD and demonstrates that the protocol cannot be generalized to higher dimensions under these principles.

Findings

High-dimensional encoding can increase key rates and noise resilience.

Twin-Field QKD cannot be extended to higher dimensions according to the defined framework.

Abstract

Twin-Field Quantum Key Distribution (QKD) is a QKD protocol that uses single-photon interference to perform QKD over long distances. QKD protocols that encode information using high-dimensional quantum states can benefit from increased key rates and higher noise resilience. We define the essence of Twin-Field QKD and explore its generalization to higher dimensions. Further, we show that, ultimately, the Twin-Field protocol cannot be generalized to higher dimensions in accordance with our definition.