Interfering-or-not-interfering quantum key distribution with advantage distillation

TL;DR

This paper enhances the interfer-ing-or-not-interfering quantum key distribution protocol by adding advantage distillation, significantly increasing transmission distance and secret key rate under realistic errors without changing the experimental setup.

Contribution

Introduces advantage distillation into INI-QKD to improve performance and transmission distance under practical error conditions.

Findings

Advantage distillation increases transmission distance.

Performance improvement is notable under high error rates.

No change to experimental setup needed.

Abstract

Interfering-or-not-interfering quantum key distribution (INI-QKD) is an innovative protocol whose performance surpasses existing twin-field protocol variants. In this study, we introduce an additional step of advantage distillation (AD) after the quantum communication phase to further enhance its performance. Through the AD the raw key is partitioned into small blocks of bits to identify highly correlated bit pairs. We numerically compute the optimal partitioning for different realistic conditions. Our results show that by employing the advantage distillation the transmission distance is significantly increased and thus can potentially improve the secret key rate of INI-QKD. This in particular is most prominent in the presence of high polarization misalignment error rates and considerable phase mismatch, all without altering the experimental setup of the protocol.