2020/12/31 by Eleftherios Moschandreou, Brian J. Rollick, Bing Qi +1
Computer Science · Engineering · Physics and Astronomy · #BB84 #Channel (broadcasting) #Computational physics #Computer science #Cutoff #Optical Network Technologies #Optics #Orbital Angular Momentum in Optics #Photon #Physics #Quantum #Quantum Information and Cryptography #Quantum cryptography #Quantum information #Quantum key distribution #Quantum mechanics #Telecommunications #Transmittance #Turbulence #quant-ph
paper · pdf · doi:10.1103/physreva.103.032614
published as Phys. Rev. A 103, 032614 (2021) · v2: 9 pages, 6 figures, improved discussion, to appear in PRA
openalex created_date 2020/12/21 · arxiv created 2021/03/19 · openalex publication_date 2021/03/26 · arxiv updated 2021/03/31 · openalex updated_date 2026/08/05
In free-space quantum key distribution (QKD) in turbulent conditions, scattering and beam wandering cause intensity fluctuations which decrease the detected signal-to-noise ratio. This effect can be mitigated by rejecting received bits when the channel's transmittance is below a threshold. Thus, the overall error rate is reduced and the secure key rate increases despite the deletion of bits. In this work, we implement recently proposed selection methods focusing on the prefixed-threshold real-time selection (P-RTS) where a cutoff can be chosen prior to data collection and independently of the transmittance distribution. We perform finite-size decoy-state Bennett-Brassard 1984 QKD in a laboratory setting where we simulate the atmospheric turbulence using an acousto-optical modulator. We show that P-RTS can yield considerably higher secure key rates for a wide range of the atmospheric channel parameters. In addition, we evaluate the performance of the P-RTS method for a realistically finite sample size. We demonstrate that a near-optimal selection threshold can be predetermined even with imperfect knowledge of the channel transmittance distribution parameters.