Single-emitter quantum key distribution over 175 km of fibre with optimised finite key rates

Morrison, Christopher L. and Pousa, Roberto G. and Graffitti, Francesco and Koong, Zhe Xian and Barrow, Peter and Stoltz, Nick G. and Bouwmeester, Dirk and Jeffers, John and Oi, Daniel K. L. and Gerardot, Brian D. and Fedrizzi, Alessandro (2023) Single-emitter quantum key distribution over 175 km of fibre with optimised finite key rates. Nature Communications, 14 (1). 3573. ISSN 2041-1723 (https://doi.org/10.1038/s41467-023-39219-5)

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Abstract

Quantum key distribution with solid-state single-photon emitters is gaining traction due to their rapidly improving performance and compatibility with future quantum networks. Here we emulate a quantum key distribution scheme with quantum-dot-generated single photons frequency-converted to 1550 nm, achieving count rates of 1.6 MHz with g20=3.6% and asymptotic positive key rates over 175 km of telecom fibre. We show that the commonly used finite-key analysis for non-decoy state QKD drastically overestimates secure key acquisition times due to overly loose bounds on statistical fluctuations. Using the tighter multiplicative Chernoff bound to constrain the estimated finite key parameters, we reduce the required number of received signals by a factor 108. The resulting finite key rate approaches the asymptotic limit at all achievable distances in acquisition times of one hour, and at 100 km we generate finite keys at 13 kbps for one minute of acquisition. This result is an important step towards long-distance single-emitter quantum networking.

  • Item type:Article
    ID code:85843
    Dates:
    Date
    Event
    16 June 2023
    Published
    5 June 2023
    Accepted
    7 September 2022
    Submitted
    Subjects:Science > Physics > Optics. Light
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:19 Jun 2023 15:33
    Last modified:25 Apr 2024 01:34
    URI:https://strathprints.strath.ac.uk/id/eprint/85843
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