2019/08/13 by Róbert Trényi, Koji Azuma, Marcos Curty
Computer Science · Physics and Astronomy · #Beat (acoustics) #Parametric statistics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum key distribution #Robustness (evolution) #Upper and lower bounds #quant-ph
paper · pdf · doi:10.1088/1367-2630/ab54aa
published as New J. Phys. 21, 113052 (2019) · 21 pages, 8 figures
arxiv created 2019/08/13 · openalex created_date 2019/08/22 · openalex publication_date 2019/11/01 · arxiv updated 2020/01/22 · openalex updated_date 2026/08/05
Abstract Surpassing the repeaterless bound is a crucial task on the way towards realizing long-distance quantum key distribution. In this paper, we focus on the protocol proposed by Azuma et al (2015 Nat. Commun. 6 10171), which can beat this bound with idealized devices. We investigate the robustness of this protocol against imperfections in realistic setups, particularly the multiple-photon pair components emitted by practical entanglement sources. In doing so, we derive necessary conditions on the photon-number statistics of the sources in order to beat the repeaterless bound. We show, for instance, that parametric down-conversion sources do not satisfy the required conditions and thus cannot be used to outperform this bound.