2009/09/30 by Yoritoshi Adachi, Takashi Yamamoto, Masato Koashi +1
Computer Science · Physics and Astronomy · #Beam splitter #Boosting (machine learning) #Detector #Distribution (mathematics) #Ideal (ethics) #Joint probability distribution #Key (lock) #Mechanical and Optical Resonators #Photon #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum key distribution #quant-ph
paper · pdf · doi:10.1088/1367-2630/11/11/113033
published as New J. Phys. 11, 113033 (2009) · 11 pages, 3 figures; published version in New J. Phys
openalex publication_date 2009/11/17 · arxiv created 2009/11/18 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We propose a simple quantum-key-distribution (QKD) scheme for practical single-photon sources (SPSs), which works even with a moderate suppression of the second-order correlation g (2) of the source. The scheme utilizes a passive preparation of a decoy state by monitoring a fraction of the signal via an additional beam splitter and a detector at the sender's side to monitor photon-number splitting attacks. We show that the achievable distance increases with the precision with which the sub-Poissonian tendency is confirmed in higher photon-number distribution of the source, rather than with actual suppression of the multiphoton emission events. We present an example of the secure key generation rate in the case of a poor SPS with g (2) =0.19, in which no secure key is produced with the conventional QKD scheme, and show that learning the photon-number distribution up to several numbers is sufficient for achieving almost the same distance as that of an ideal SPS.