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Securing quantum key distribution systems using fewer states
- Source :
- Physical Review A. 97
- Publication Year :
- 2018
- Publisher :
- American Physical Society (APS), 2018.
-
Abstract
- Quantum key distribution (QKD) allows two remote users to establish a secret key in the presence of an eavesdropper. The users share quantum states prepared in two mutually unbiased bases: one to generate the key while the other monitors the presence of the eavesdropper. Here, we show that a general $d$-dimension QKD system can be secured by transmitting only a subset of the monitoring states. In particular, we find that there is no loss in the secure key rate when dropping one of the monitoring states. Furthermore, it is possible to use only a single monitoring state if the quantum bit error rates are low enough. We apply our formalism to an experimental $d=4$ time-phase QKD system, where only one monitoring state is transmitted, and obtain a secret key rate of $17.4\ifmmode\pm\else\textpm\fi{}2.8$ Mbits/s at a 4 dB channel loss and with a quantum bit error rate of $0.045\ifmmode\pm\else\textpm\fi{}0.001$ and $0.037\ifmmode\pm\else\textpm\fi{}0.001$ in time and phase bases, respectively, which is 58.4% of the secret key rate that can be achieved with the full setup. This ratio can be increased, potentially up to 100%, if the error rates in time and phase basis are reduced. Our results demonstrate that it is possible to substantially simplify the design of high-dimensional QKD systems, including those that use the spatial or temporal degrees of freedom of the photon, and still outperform qubit-based ($d=2$) protocols.
- Subjects :
- Physics
Quantum Physics
Photon
FOS: Physical sciences
02 engineering and technology
Quantum key distribution
021001 nanoscience & nanotechnology
Topology
01 natural sciences
Formalism (philosophy of mathematics)
Quantum state
Qubit
0103 physical sciences
Quantum bit error rate
Quantum Physics (quant-ph)
010306 general physics
0210 nano-technology
Mutually unbiased bases
Subjects
Details
- ISSN :
- 24699934 and 24699926
- Volume :
- 97
- Database :
- OpenAIRE
- Journal :
- Physical Review A
- Accession number :
- edsair.doi.dedup.....41b627e48c76cd99024cdfd7d9c76c80