Non-Gaussianity and security of entanglement-based QKD

TL;DR

This paper investigates how non-Gaussianity relates to the security of entanglement-based quantum key distribution protocols, considering realistic imperfections and different noise models to assess channel suitability for secure communication.

Contribution

It provides a theoretical analysis connecting non-Gaussianity with security in entanglement-based QKD, including effects of detection imperfections and various noise statistics.

Findings

Cross-regions identified for security and non-Gaussianity indicating channel suitability.

Analysis includes imperfect detection with dark counts and limited efficiency.

Results can serve as a pre-check for QKD implementation.

Abstract

We theoretically analyse the relation between non-Gaussianity and security of entanglement-based quantum key distribution (QKD) protocols, namely device-independent (DI) and entanglement-based BB$84$. A similar analysis has already been made for prepare-and-measure (P\&M) protocols \cite{Lasota2017}. In addition, we consider imperfect detection with dark counts and limited efficiency. We assume a perfect source of entangled Bell states as produced by quantum-dot type sources, depolarisation in the channel and different noise statistics, namely thermal and Poissonian. We consider single-photon avalanche photodiodes (SPAD) and photon number resolving detectors (PNRD) and use their respective criteria for non-Gaussianity. The results show cross-regions for both security and non-Gaussianity, hence, the possibility to conclude about the suitability of a given channel for secret key distribution. Our results can be useful as a pre-check for the implementation of QKD protocols.