Quantum channel using photon number correlated twin beams

Zhang, Yun; Kasai, Katsuyuki; Hayasaka, Kazuhiro

doi:10.1364/oe.11.003592

Cited by 16 publications

(7 citation statements)

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“…Typically the continuous quadrature observables are used to encode key bits, and subsequently, the homodyne detection of the quadrature (or heterodyne measurement of two complementary quadratures simultaneously) is applied contrary to the photon-counting measurement in DV QKD. Alternatively, polarization [23] or photon-number coding [24][25][26][27][28] can in principle be used. The preliminary version of CV QKD was firstly suggested [29] and studied against particular eavesdropping strategies [30] by Ralph based on the binary quadrature displacement of coherent state produced by a laser or two-mode quadrature-squeezed states, which can be produced by an optical parametric oscillator.…”

Section: Introductionmentioning

confidence: 99%

Trusted Noise in Continuous-Variable Quantum Key Distribution: A Threat and a Defense

Usenko

Filip

2016

Entropy

104

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Abstract:We address the role of the phase-insensitive trusted preparation and detection noise in the security of a continuous-variable quantum key distribution, considering the Gaussian protocols on the basis of coherent and squeezed states and studying them in the conditions of Gaussian lossy and noisy channels. The influence of such a noise on the security of Gaussian quantum cryptography can be crucial, even despite the fact that a noise is trusted, due to a strongly nonlinear behavior of the quantum entropies involved in the security analysis. We recapitulate the known effect of the preparation noise in both direct and reverse-reconciliation protocols, as well as the detection noise in the reverse-reconciliation scenario. As a new result, we show the negative role of the trusted detection noise in the direct-reconciliation scheme. We also describe the role of the trusted preparation or detection noise added at the reference side of the protocols in improving the robustness of the protocols to the channel noise, confirming the positive effect for the coherent-state reverse-reconciliation protocol. Finally, we address the combined effect of trusted noise added both in the source and the detector.

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Section: Introductionmentioning

confidence: 99%

Trusted Noise in Continuous-Variable Quantum Key Distribution: A Threat and a Defense

Usenko

Filip

2016

Entropy

104

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“…Generation of PNES have been reported with photon-number statistics varying from sub-Poisson [11] to superPoisson [12][13][14]. As a matter of fact, several quantum communication schemes and QKD protocols have been proposed exploiting PNES correlations with coding based on the beams intensity [6,15] or intensity difference [16]. In particular, the degenerate pair-coherent states [17,18], also referred to as two-mode coherently correlated (TMC) [7] have been suggested as an effective channel.…”

Section: Binary Communication With Photon-number Entangled Statesmentioning

confidence: 99%

Quantum communication with photon-number entangled states and realistic photodetection

Usenko

Paris

2010

Physics Letters A

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We address the effects of realistic photodetection, with nonunit quantum efficiency and background noise (dark counts), on the performances of quantum communication schemes based on photon-number entangled states (PNES). We consider channels based on Gaussian twin-beam states (TWB) and nonGaussian two-mode coherent states (TMC) and evaluate the channel capacity by optimizing the bit discrimination threshold. We found that TWB-based channels are more robust against noise than TMCbased ones and that this result is almost independent on the statistics of dark counts.

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“…In this work we propose and examine the cryptographic method based on the use of a correlated two-mode laser beam for a secure key generation and transmission between two sites. Such and similar beams are actively experimentally studied last time [12,13,14]. Therefore we examine in detail the properties of the states, which describe the two-mode correlated laser beams, investigate the dependence of these properties on the beam intensity, and analyze the possibility to use such beams in the data channels.…”

Section: Introductionmentioning

confidence: 99%