{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T09:41:31Z","timestamp":1771234891586,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2022,4,23]],"date-time":"2022-04-23T00:00:00Z","timestamp":1650672000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["12074194, U19A2075, 12104240, 62101285"],"award-info":[{"award-number":["12074194, U19A2075, 12104240, 62101285"]}]},{"name":"National Key R&amp;D Program 146 of China","award":["2018YFA0306400, 2017YFA0304100"],"award-info":[{"award-number":["2018YFA0306400, 2017YFA0304100"]}]},{"name":"Leading-edge technology Program of Jiangsu Natural 148 Science Foundation","award":["BK20192001"],"award-info":[{"award-number":["BK20192001"]}]},{"name":"Natural Science Foundation of Jiangsu Province","award":["BK20210582"],"award-info":[{"award-number":["BK20210582"]}]},{"name":"NUPTSF","award":["NY220122, NY220123"],"award-info":[{"award-number":["NY220122, NY220123"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Twin-field quantum key distribution (TF-QKD) can break the repeaterless linear bound and possess the measurement-device-independent security, and thus seems very promising in practical applications of quantum secure communication. In most reported TF-QKD protocols, light sources are assumed to possess trusted and fixed photon number distributions (PND), which are unrealistic assumptions in practical applications. Fortunately, the light source monitoring (LSM) method is proposed to circumvent this problem by actively adjusting the attenuation coefficient and monitoring the photon number distribution of light sources. However, the active light source monitoring (ALSM) method may induce additional modulation errors due to imperfect attenuation devices, deteriorating practical performances of TF-QKD systems. In this manuscript, we propose a passive light source monitoring (PLSM) scheme for TF-QKD, and employ the sending-or-not-sending (SNS) TF-QKD as an example for illustration. Simulation results show that our present work can greatly exceed both the original SNS protocol and the ALSM scheme when light source fluctuations and modulation errors are taken into account.<\/jats:p>","DOI":"10.3390\/e24050592","type":"journal-article","created":{"date-parts":[[2022,4,23]],"date-time":"2022-04-23T08:14:06Z","timestamp":1650701646000},"page":"592","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Passive Light Source Monitoring for Sending or Not Sending Twin-Field Quantum Key Distribution"],"prefix":"10.3390","volume":"24","author":[{"given":"Xuerui","family":"Qian","sequence":"first","affiliation":[{"name":"Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China"},{"name":"Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China"},{"name":"Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7225-2870","authenticated-orcid":false,"given":"Chunhui","family":"Zhang","sequence":"additional","affiliation":[{"name":"Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China"},{"name":"Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China"},{"name":"Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huawei","family":"Yuan","sequence":"additional","affiliation":[{"name":"Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China"},{"name":"Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China"},{"name":"Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8965-8009","authenticated-orcid":false,"given":"Xingyu","family":"Zhou","sequence":"additional","affiliation":[{"name":"Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China"},{"name":"Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China"},{"name":"Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jian","family":"Li","sequence":"additional","affiliation":[{"name":"Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China"},{"name":"Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China"},{"name":"Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6314-4250","authenticated-orcid":false,"given":"Qin","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China"},{"name":"Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China"},{"name":"Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.tcs.2014.05.025","article-title":"Quantum cryptography: Public key distribution and coin tossing","volume":"560","author":"Bennett","year":"2014","journal-title":"Theor. 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