Author
Listed:
- Wei Zhang
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- Tim Leent
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- Kai Redeker
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- Robert Garthoff
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- René Schwonnek
(Universität Siegen
National University of Singapore)
- Florian Fertig
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- Sebastian Eppelt
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- Wenjamin Rosenfeld
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST))
- Valerio Scarani
(National University of Singapore
National University of Singapore)
- Charles C.-W. Lim
(National University of Singapore
National University of Singapore
JPMorgan Chase)
- Harald Weinfurter
(Ludwig-Maximilians-Universität
Munich Center for Quantum Science and Technology (MCQST)
Max-Planck Institut für Quantenoptik)
Abstract
Device-independent quantum key distribution (DIQKD) enables the generation of secret keys over an untrusted channel using uncharacterized and potentially untrusted devices1–9. The proper and secure functioning of the devices can be certified by a statistical test using a Bell inequality10–12. This test originates from the foundations of quantum physics and also ensures robustness against implementation loopholes13, thereby leaving only the integrity of the users’ locations to be guaranteed by other means. The realization of DIQKD, however, is extremely challenging—mainly because it is difficult to establish high-quality entangled states between two remote locations with high detection efficiency. Here we present an experimental system that enables for DIQKD between two distant users. The experiment is based on the generation and analysis of event-ready entanglement between two independently trapped single rubidium atoms located in buildings 400 metre apart14. By achieving an entanglement fidelity of $$ {\mathcal F} \,\ge 0.892(23)$$ ℱ ≥ 0.892 ( 23 ) and implementing a DIQKD protocol with random key basis15, we observe a significant violation of a Bell inequality of S = 2.578(75)—above the classical limit of 2—and a quantum bit error rate of only 0.078(9). For the protocol, this results in a secret key rate of 0.07 bits per entanglement generation event in the asymptotic limit, and thus demonstrates the system’s capability to generate secret keys. Our results of secure key exchange with potentially untrusted devices pave the way to the ultimate form of quantum secure communications in future quantum networks.
Suggested Citation
Wei Zhang & Tim Leent & Kai Redeker & Robert Garthoff & René Schwonnek & Florian Fertig & Sebastian Eppelt & Wenjamin Rosenfeld & Valerio Scarani & Charles C.-W. Lim & Harald Weinfurter, 2022.
"A device-independent quantum key distribution system for distant users,"
Nature, Nature, vol. 607(7920), pages 687-691, July.
Handle:
RePEc:nat:nature:v:607:y:2022:i:7920:d:10.1038_s41586-022-04891-y
DOI: 10.1038/s41586-022-04891-y
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Citations
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Cited by:
- Jie Zhao & Hao Jeng & Lorcán O. Conlon & Spyros Tserkis & Biveen Shajilal & Kui Liu & Timothy C. Ralph & Syed M. Assad & Ping Koy Lam, 2023.
"Enhancing quantum teleportation efficacy with noiseless linear amplification,"
Nature Communications, Nature, vol. 14(1), pages 1-8, December.
- Peter Schiansky & Julia Kalb & Esther Sztatecsny & Marie-Christine Roehsner & Tobias Guggemos & Alessandro Trenti & Mathieu Bozzio & Philip Walther, 2023.
"Demonstration of quantum-digital payments,"
Nature Communications, Nature, vol. 14(1), pages 1-7, December.
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