Prefixed-threshold real-time selection method in free-space quantum key distribution

Wang, Wenyuan; Xu, Feihu; Lo, Hoi-Kwong

doi:10.1103/physreva.97.032337

Cited by 42 publications

(33 citation statements)

References 38 publications

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“…It has been shown that a post-selection of the time-intervals with greater transmittance can help to increase the secret key rates [48][49][50]: in this context, the ability of our approach to simulate not only the expected value of the transmittance, but its probability distribution too, may prove to be of great interest. In [51] the authors showed that the detrimental effects of asymmetric and fluctuating losses in measurement-device-independent QKD with decoy states can be counteracted by means of additional losses introduced by the central node.…”

Section: Satellite-based Links: Model and Resultsmentioning

confidence: 99%

Satellite-based links for quantum key distribution: beam effects and weather dependence

2019

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The establishment of a world-wide quantum communication network relies on the synergistic integration of satellite-based links and fiber-based networks. The first are helpful for long-distance communication, as the photon losses introduced by the optical fibers are too detrimental for lengths greater than about 200 km. This work aims at giving, on the one hand, a comprehensive and fundamental model for the losses suffered by the quantum signals during the propagation along an atmospheric free-space link. On the other hand, a performance analysis of different quantum key distribution (QKD) implementations is performed, including finite-key effects, focusing on different interesting practical scenarios. The specific approach that we chose allows to precisely model the contribution due to different weather conditions, paving the way towards more accurate feasibility studies of satellite-based QKD missions. IntroductionQuantum key distribution (QKD) and quantum communication in general have the potential to revolutionise the way we communicate confidential information over the internet. The natural carriers for quantum information are photons, that are already widely used in classical networks of optical fibers to achieve high communication rates. Unfortunately, even though enormous improvements have been obtained in the last years [1, 2], scaling quantum communication protocols over long distances is very challenging, due to the losses experienced during the propagation inside the optical fibers. Several schemes for the realization of quantum repeaters have been proposed in recent years, that could allow to bridge long distances and naturally be implemented inside a quantum communication network [3][4][5][6][7]. Considering the important technological hurdles that quantum repeaters should overcome before becoming useful, satellite-based free-space links look like the most practical way to achieve long-distance QKD in the short term [8]. They can take advantage of the satellite technology and the optical communication methods developed in the last decades in the classical case. Various feasibility studies had addressed this topic in the last twenty years [8][9][10][11] and several experiments have definitely proved that the technology involved is ready for deployment [12][13][14][15][16].Optical satellite-based links have the important drawback of being strongly dependent on the weather conditions [17][18][19][20]. The presence of turbulent eddies and scattering particles like haze or fog generates random fluctuations of the relative permittivity of the air, on different length-and time-scales. This phenomenon affects the light propagation in a complicated way, inducing random deviations and deformations of any optical beam sent through the atmosphere. It results in reduced transmittance, because of geometrical losses due to the finite collection aperture, and random modifications of the phase front. A comprehensive model of these effects is then necessary, in order to precisely evaluate the performance of the link w...

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Section: Satellite-based Links: Model and Resultsmentioning

confidence: 99%

Satellite-based links for quantum key distribution: beam effects and weather dependence

2019

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“…[7] the successful implementation of this protocol was shown for the 144-km atmospheric channel between two Canary Islands. The theoretical analysis of the performance of the decoy-state protocol that utilizes atmospheric quantum channels is given in [15,31,77] and the experimental realization is demonstrated in [25]. The transmitter Alice encodes the pulses in a signal and two decoy states and sends them to the receiver Bob.…”

Section: Decoy-state Quantum Communication Through Turbulent Optical ...mentioning

confidence: 99%

Theory of atmospheric quantum channels based on the law of total probability

2018

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The atmospheric turbulence is the main factor that influences quantum properties of propagating optical signals and may sufficiently degrade the performance of quantum communication protocols. The probability distribution of transmittance (PDT) for free-space channels is the main characteristics of the atmospheric links. Applying the law of total probability, we derive the PDT by separating the contributions from turbulence-induced beam wandering and beam-spot distortions. As a result, the obtained PDT varies from log-negative Weibull to truncated log-normal distributions depending on the channel characteristics. Moreover, we show that the method allows one to consistently describe beam tracking, a procedure which is typically used in practical long-distance free-space quantum communication. We analyze the security of decoy-state quantum key exchange through the turbulent atmosphere and show that beam tracking does not always improves quantum communication.

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“…On the contrary, the approach used here is a constructive method that allows to determine the PDT starting from the characteristics of the beam and the atmospheric conditions. It has been shown that a post-selection of the time-intervals with greater transmittance can help to increase the secret key rates [47,48,49]: in this context, the ability of our approach to simulate not only the expected value of the transmittance, but its probability distribution too, may prove to be of great interest. Finally, we effectively take into account the contribution due to scattering particles, like fog or haze, making possible to model the effect of different weather conditions, a problem usually not addressed in previous works.…”

Section: Satellite-based Links: Model and Resultsmentioning

confidence: 99%

Satellite-based links for Quantum Key Distribution: beam effects and weather dependence

Liorni,

Kampermann,

Bruß

2019

Preprint

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Prefixed-threshold real-time selection method in free-space quantum key distribution

Cited by 42 publications

References 38 publications

Satellite-based links for quantum key distribution: beam effects and weather dependence

Satellite-based links for quantum key distribution: beam effects and weather dependence

Theory of atmospheric quantum channels based on the law of total probability

Satellite-based links for Quantum Key Distribution: beam effects and weather dependence

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