Detector-decoy high-dimensional quantum key distribution

TL;DR

This paper introduces a detector-decoy high-dimensional quantum key distribution protocol that simplifies implementation and improves performance over existing methods, especially with lower detector efficiency.

Contribution

It proposes a novel detector-decoy protocol using threshold detectors and a variable attenuator, enhancing practicality and performance without varying source intensity.

Findings

Outperforms one-decoy-state protocol in key rate.

Comparable to two-decoy-state protocol without source intensity variation.

More advantageous with lower detector efficiency.

Abstract

The decoy-state high-dimensional quantum key distribution provides a practical secure way to share more private information with high photon-information efficiency. In this paper, based on detector-decoy method, we propose a detector-decoy high-dimensional quantum key distribution protocol. Employing threshold detectors and a variable attenuator, we can estimate single-photon fraction of postselected events and Eves Holevo information under the Gaussian collective attack with much simpler operations in practical implementation. By numerical evaluation, we show that without varying source intensity and optimizing decoy-state intensity, our protocol could perform much better than one-decoy-state protocol and as well as the two-decoy-state protocol. Specially, when the detector efficiency is lower, the advantage of the detector-decoy method becomes more prominent.