{"id":39,"date":"2022-09-12T12:13:08","date_gmt":"2022-09-12T10:13:08","guid":{"rendered":"http:\/\/quantaquest-padr.eu\/?p=39"},"modified":"2022-09-12T12:13:08","modified_gmt":"2022-09-12T10:13:08","slug":"qkd-links-by-unipd","status":"publish","type":"post","link":"https:\/\/quantaquest-padr.eu\/index.php\/2022\/09\/12\/qkd-links-by-unipd\/","title":{"rendered":"QKD links by UNIPD"},"content":{"rendered":"\n

A major challenge for today\u2019s communication networks is to ensure safe
exchange of sensitive data between distant parties. However, the rapid
development of quantum information protocols towards the quantum
computer poses a substantial threat for current cyber-security systems. In
fact, quantum routines such as Shor\u2019s factorization algorithm could
potentially render today\u2019s cryptographic schemes obsolete and
completely insecure. Fortunately, quantum key distribution (QKD)
represents a solution to this catastrophic scenario. By leveraging on the
principles of quantum mechanics and the characteristics of photons, QKD
allows two distant parties, conventionally called Alice and Bob, to distill a
perfectly secret key and bound the shared information with any
adversarial eavesdropper. Furthermore, QKD is an interesting solution for
applications requiring long- term privacy, since algorithmic and
technological advances for both classical and quantum computation do
not threaten the security of keys generated with QKD.
The expertise of the QuantumFuture<\/a> research group of the University of
Padova, in quantum communication dates back to the beginning of 2000s,
when professor Villoresi started collaborating with the Matera Laser
Ranging Observatory (MLRO) of the Italian Space Agency. By exploiting
satellite-laser-ranging to emulate a single-photon source in Space,
QuantumFuture group run different pioneeristic experiments
demostrating the capability of detecting single-photon coming from
satellites in LEO [1]<\/a>, MEO [2]<\/a> and GNSS orbits [3]<\/a>, as well as the feasibility of
implementing different quantum information encodings, such as
polarization [4]<\/a> and time-bin [5]<\/a> along satellite channels. This series of
experiments culminated with the realization of a fundamental test of
Quantum Mechanics in Space, the so-called Wheeler\u2019s delayed-choice
experiment [6]<\/a>.
Meanwhile, the group realized various QKD experiments over horizontal
links in free-space, in which it is crucial to face the detrimental effects due
to atmospheric turbulence. For example, a 143km-long QKD link between two Canary islands was implemented in 2015 to test a new technique to
mitigate the effects [7]<\/a>. More recently, the most long-lasting daylight QKD
has been performed in an urban environment [8]<\/a>, taking advantages of
integrated photonics technology and adaptive-optics correction at the
receiver.
The group introduced new schemes and devices for the generation of high-
quality polarization-states for QKD: the POGNAC encoder [9]<\/a> and its
improved version, the iPOGNAC [10]<\/a>, show intrinsic long-term stability and
a record-low quantum bit error rate [11]<\/a>. The above devices, together with
a novel syncronization techique for QKD named Qubit4Sync [12]<\/a>, are at the
core of the QKD technology offered by ThinkQuantum. Moreover, the
robustness of iPOGNAC makes it a suitable solution to design quantum
satellite payloads. <\/p>\n\n\n\n

References<\/p>\n\n\n\n

[1] P. Villoresi, T. Jennewein, F. Tamburini, M. Aspelmeyer, C. Bonato, R. Ursin, C. Pernechele, V. Luceri, G. Bianco, A. Zeilinger, C. Barbieri, Experimental verification of the feasibility of a quantum channel between space and Earth, New J. Phys., 10, 033038 (2008)<\/p>\n\n\n\n

[2] D. Dequal, G. Vallone, D. Bacco, S. Gaiarin, V. Luceri, G. Bianco, P. Villoresi, Experimental single-photon exchange along a space link of 7000 km, Phys. Rev. A, 93, 010301(R) (2016)<\/p>\n\n\n\n

[3] L. Calderaro, C. Agnesi, D. Dequal, F. Vedovato, M. Schiavon, A. Santamato, V. Luceri, G. Bianco, G. Vallone, P. Villoresi, Towards quantum communication from global navigation satellite system, Quantum Sci. Technol., 4, 015012 (2018)<\/p>\n\n\n\n

[4] G. Vallone, D. Bacco, D. Dequal, S. Gaiarin, V. Luceri, G. Bianco, P. Villoresi, Experimental Satellite Quantum Communications, Phys. Rev. Lett., 115, 040502 (2015)<\/p>\n\n\n\n

[5] G. Vallone, D. Dequal, M. Tomasin, F. Vedovato, M. Schiavon, V. Luceri, G. Bianco, P. Villoresi, Phys. Rev. Lett., 116, 253601 (2016)<\/p>\n\n\n\n

[6] F. Vedovato, C. Agnesi, M. Schiavon, D. Dequal, L. Calderaro, M. Tomasin, D. G. Marangon, A. Stanco, V. Luceri, G. Bianco, G. Vallone, P. Villoresi, Extending Wheeler’s delayed-choice experiment to space, Science Advances, 3, 10 (2017) <\/p>\n\n\n\n

[7] G. Vallone, D. G. Marangon, M. Canale, I. Savorgnan, D. Bacco, M. Barbieri, S. Calimani, C. Barbieri, N. Laurenti, P. Villoresi, Adaptive real time selection for quantum key distribution in lossy and turbulent free-space channels, Phys. Rev. A, 91, 042320 (2015)<\/p>\n\n\n\n

[8] M. Avesani, L. Calderaro, M. Schiavon, A. Stanco, C. Agnesi, A. Santamato, M. Zahidy, A. Scriminich, G. Foletto, G. Contestabile, M. Chiesa, D. Rotta, M. Artiglia, A. Montanaro, M. Romagnoli, V. Sorianello, F. Vedovato, G. Vallone, P. Villoresi, Full daylight quantul-key-distribution at 1550 nm enabled by integrated silicon photonics, npj Quantum Information, 7, 93 (2021)<\/p>\n\n\n\n

[9] C. Agnesi, M. Avesani, A. Stanco, P. Villoresi, G. Vallone, All-fiber self-compensating polarization encoder for quantum key distribution, Opt. Lett., 44, 2398-2401 (2019)<\/p>\n\n\n\n

[10] M. Avesani, C. Agnesi, A. Stanco, G. Vallone, P. Villoresi, Stable, low-error, and calibration-free polarization encoder for free-space quantum communication, Opt. Lett., 45, 4706-4709 (2020)<\/p>\n\n\n\n

[11] C. Agnesi, M. Avesani, L. Calderaro, A. Stanco, G. Foletto, M. Zahidy, A. Scriminich, F. Vedovato, G. Vallone, P. Villoresi, Simple quantum key distribution with qubit-based synchronization and a self-compensating polarization encoder, Optica, 7, 284-290 (2020)<\/p>\n\n\n\n

[12] L. Calderaro, A. Stanco, C. Agnesi, M. Avesani, D. Dequal, P. Villoresi, G. Vallone, Fast and Simple Qubit-Based Synchronization for Quantum Key Distribution, Phys. Rev. Applied, 13, 050441 (2020)<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

A major challenge for today\u2019s communication networks is to ensure safeexchange of sensitive data between distant parties. However, the rapiddevelopment of quantum information protocols towards the quantumcomputer poses a substantial threat for current cyber-security systems. Infact, quantum routines such as Shor\u2019s factorization algorithm couldpotentially render today\u2019s cryptographic schemes obsolete andcompletely insecure. Fortunately, quantum key distribution […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-39","post","type-post","status-publish","format-standard","hentry","category-non-classe"],"_links":{"self":[{"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/posts\/39","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/comments?post=39"}],"version-history":[{"count":3,"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/posts\/39\/revisions"}],"predecessor-version":[{"id":59,"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/posts\/39\/revisions\/59"}],"wp:attachment":[{"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/media?parent=39"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/categories?post=39"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/quantaquest-padr.eu\/index.php\/wp-json\/wp\/v2\/tags?post=39"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}