Adaptive Measurement-Device-Independent Quantum Key Distribution

TL;DR

This paper advances quantum key distribution by replacing threshold detectors with photon-number resolving detectors in adaptive measurement-device-independent protocols, enhancing realism and potentially extending secure communication distances.

Contribution

It introduces a more realistic implementation of AMDI-QKD using photon-number resolving detectors and analyzes its key rate and error rate dependence on transmission distance.

Findings

Photon-number resolving detectors improve protocol realism.

Secret key rate decreases with transmission distance.

QBER depends on transmission distance.

Abstract

In theory, quantum key distribution (QKD) promises unconditional secure generation of the key between two remote participants, based on the laws of quantum physics. However, because of the imperfections in the real-life implementation of QKD, this promise fails. To fill the gap between the theory and implementation of QKD, different protocols have been proposed. One of them is measurement device independent (MDI) QKD, which can be implemented using present-day technology and generates a reasonable key rate. The protocol works perfectly fine for intracity communication. However, the transmission distance is not enough, so that it can replace intercity communication. For that, adaptive measurement device-independent (AMDI) QKD has been proposed. So, the present-day classical communication network such as the internet can be replaced with its quantum version. Till the date, AMDI-QKD has been implemented with threshold detectors. In this paper, we replaced threshold detectors with photon-number resolving detectors, thus making the protocol more realistic. We calculated the secret key rate for the case and discussed its dependence on transmission distance. We also discussed the dependence of the sifted key rate and quantum bit error rate (QBER) on the transmission distance.