Quantum Key Distribution with a Negatively Charged Quantum Dot Single-Photon Source

TL;DR

This paper investigates a negatively charged quantum dot single-photon source for quantum key distribution, demonstrating that adiabatic rapid passage enhances photon quality and secure key rates compared to resonant excitation and Poisson-distributed sources.

Contribution

It introduces a quantum-dot single-photon source driven by ARP, showing improved photon indistinguishability and secure key rates for QKD protocols over traditional sources.

Findings

ARP excitation suppresses multiphoton emission

Quantum-dot sources outperform PDS at short/intermediate distances

Long-distance performance favors PDS sources in certain regimes

Abstract

Various quantum key distribution (QKD) protocols require bright single-photon sources with a very low probability of multiphoton emission. In this work, we investigate single-photon generation from a negatively charged quantum dot embedded in an elliptical pillar microcavity, driven by either resonant excitation or adiabatic rapid passage (ARP). Our results show that ARP excitation significantly suppresses multiphoton emission and improves photon indistinguishability compared to resonant excitation. We further evaluate the secure key rates of both BB84 and twin-field QKD (TF-QKD) using a quantum-dot single-photon source and compare its performance with that of Poisson-distributed sources (PDS), such as weak coherent pulses. The analysis reveals that ARP provides a modest but consistent enhancement in secure key rate relative to resonant excitation. We show that quantum-dot single-photon sources offer improved performance compared to PDS sources at short and intermediate distances within the chosen parameter regime; however, at longer distances, PDS sources slightly surpass them in both decoy-state BB84 and TF-QKD under the same conditions.