{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,16]],"date-time":"2026-01-16T02:27:21Z","timestamp":1768530441971,"version":"3.49.0"},"reference-count":17,"publisher":"American Association of Physics Teachers (AAPT)","issue":"1","funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/50008\/2020"],"award-info":[{"award-number":["UIDB\/50008\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["2021.03707.CEECIND\/CP1653\/CT0002"],"award-info":[{"award-number":["2021.03707.CEECIND\/CP1653\/CT0002"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["DIGITAL-2021-QCI-01"],"award-info":[{"award-number":["DIGITAL-2021-QCI-01"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2025,1,1]]},"abstract":"<jats:p>Quantum key distribution (QKD) has become an essential technology in the realm of secure communication, with applications ranging from secure data transmission to quantum networks. This paper presents a simple, compact, and cost-effective setup for undergraduate tutorial demonstrations of QKD. It relies on using weak coherent pulses, which can be readily produced using an attenuated laser. The system employs the simplified three-state BB84 protocol in free space, with states encoded using linear polarization. Polarization encoding can be done passively or actively, depending on the budget available. Time multiplexing is implemented at the receiver to reduce the number of required detectors. Only two detectors are used to implement measurements on two bases, with a total of four outcomes. The result demonstrates the practicality of the system for free-space quantum communication, and its compact and portable nature makes it particularly suitable for pedagogical demonstrations. This work paves the way for engaging undergraduate students in the field of quantum communication through hands-on laboratory projects.<\/jats:p>","DOI":"10.1119\/5.0204077","type":"journal-article","created":{"date-parts":[[2024,12,23]],"date-time":"2024-12-23T13:37:06Z","timestamp":1734961026000},"page":"69-77","update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":3,"title":["Simple portable quantum key distribution for science outreach"],"prefix":"10.1119","volume":"93","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-1924-0407","authenticated-orcid":false,"given":"Pedro","family":"Neto Mendes","sequence":"first","affiliation":[{"name":"Departamento de Engenharia Electrot\u00e9cnica e de Computadores, Instituto Superior T\u00e9cnico , 1049-001 Lisbon, and , 1049-001 Lisbon,","place":["Portugal Portugal"]},{"name":"Instituto de Telecomunica\u00e7\u00f5es , 1049-001 Lisbon, and , 1049-001 Lisbon,","place":["Portugal Portugal"]}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6276-4976","authenticated-orcid":false,"given":"Paulo","family":"Andr\u00e9","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia Electrot\u00e9cnica e de Computadores, Instituto Superior T\u00e9cnico , 1049-001 Lisbon, and , 1049-001 Lisbon,","place":["Portugal Portugal"]},{"name":"Instituto de Telecomunica\u00e7\u00f5es , 1049-001 Lisbon, and , 1049-001 Lisbon,","place":["Portugal Portugal"]}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3418-9131","authenticated-orcid":false,"given":"Emmanuel","family":"Zambrini Cruzeiro","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es , 1049-001 Lisbon,","place":["Portugal"]}]}],"member":"3","reference":[{"key":"2024122313365200800_c1","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1016\/j.tcs.2014.05.025","article-title":"Quantum cryptography: Public key distribution and coin tossing","volume":"560","year":"2014","journal-title":"Theor. 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Photonics"},{"key":"2024122313365200800_c16","unstructured":"The code is available on the Github page https:\/\/github.com\/QuLab-IT\/QuantSatSimulator.git."},{"key":"2024122313365200800_c17","unstructured":"See https:\/\/www.idquantique.com\/quantum-safe-security\/products\/clavis-xgr-qkd-platform\/ for Clavis XGR QKD."}],"container-title":["American Journal of Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.aip.org\/aapt\/ajp\/article-pdf\/93\/1\/69\/20309845\/69_1_5.0204077.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.aip.org\/aapt\/ajp\/article-pdf\/93\/1\/69\/20309845\/69_1_5.0204077.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,12,23]],"date-time":"2024-12-23T13:37:08Z","timestamp":1734961028000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.aip.org\/ajp\/article\/93\/1\/69\/3327085\/Simple-portable-quantum-key-distribution-for"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,1,1]]},"references-count":17,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2025,1,1]]}},"URL":"https:\/\/doi.org\/10.1119\/5.0204077","relation":{},"ISSN":["0002-9505","1943-2909"],"issn-type":[{"value":"0002-9505","type":"print"},{"value":"1943-2909","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2025,1]]},"published":{"date-parts":[[2025,1,1]]}}}