Temperature effects on atmospheric continuous-variable quantum key distribution*

Zhang, Shujing; Ma, Hongxin; Wang, Xiang; Zhou, Chun; Bao, Wan-Su; Zhang, Hailong

doi:10.1088/1674-1056/28/8/080304

Cited by 3 publications

(2 citation statements)

References 27 publications

(32 reference statements)

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“…[35,36] Nevertheless, in these experimental schemes, the Stokes parameter can not be modulated arbitrarily due to the limitation of modulation devices based on free space, so the signal states can not take arbitrary continuous values in Poincare sphere space. In addition, relevant security analysis [37][38][39][40][41] does not take into account the effects of foggy weather. Aiming at these problems, we propose a new modulation method to extend the modulation range of signal states with an optical-fiber-based polarization controller.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of quantum key distribution using polarized coherent-states in free-space channel

Zheng¹,

Chen²,

Huang³

et al. 2023

Chinese Phys. B

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In free space channel, continuous-variable quantum key distribution (CV-QKD) using polarized coherent-states can not only make the signal state more stable and less susceptible to interference based on the polarization non-sensitive of the free-space channel, but also reduce the noise introduced by phase interference. However, arbitrary continuous modulation can not be carried out in the past polarization coding, resulting in that the signal state can not obtain arbitrary continuous value in Poincare space, and the security analysis of CV-QKD using polarized coherent-states in free space is not complete. Here we propose a new modulation method to extend the modulation range of signal states with an optical-fiber-based polarization controller. In particular, in terms of the main influence factors in the free-space channel, we utilize the beam extinction and elliptical model when considering the transmittance and adopt the formulation of secret key rate. In addition, the performance of the proposed scheme under foggy weather is also taken into consideration to reveal the influence of severe weather. Numerical simulation shows that the proposed scheme is seriously affected by attenuation under foggy weather. The protocol fails when visibility is less than 1 km. At the same time, the wavelength can affect the performance of the proposed scheme. Specifically, under foggy weather, the longer the wavelength, the smaller the attenuation coefficient, and the better the transmission performance. Our proposed scheme can expand the modulation range of signal state, and supplement the security research of the scheme in the free-space channel, thus can provide theoretical support for subsequent experiments.

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Section: Introductionmentioning

confidence: 99%

Performance analysis of quantum key distribution using polarized coherent-states in free-space channel

Zheng¹,

Chen²,

Huang³

et al. 2023

Chinese Phys. B

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“…Continuous-variable quantum key distribution (CVQKD) allows two distant parties, Alice and Bob, to share random secret keys over an untrusted environment controlled by an eavesdropper, Eve. [1][2][3][4] Compared with discrete-variable quantum key distribution (DVQKD), [5][6][7][8][9] CVQKD can be applied on off-the-shelf optical fiber system with relative higher secret key rate, avoiding the imperfection for using single photon counting. [10,11] In a typical optical fiber system, [12][13][14] Alice encodes Gaussian-distributed random numbers on weak coherent states and then sends them to Bob through an optical fiber.…”

Section: Introductionmentioning

confidence: 99%

Hybrid linear amplifier-involved detection for continuous variable quantum key distribution with thermal states*

He¹,

Mao²,

Zhong³

et al. 2020

Chinese Phys. B

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Continuous-variable quantum key distribution (CVQKD) can be integrated with thermal states for short-distance wireless quantum communications. However, its performance is usually restricted with the practical thermal noise. We propose a method to improve the security threshold of thermal-state (TS) CVQKD by employing a heralded hybrid linear amplifier (HLA) at the receiver. We find the effect of thermal noise on the HLA-involved scheme in near-and-mid infrared band or terahertz band for direct and reverse reconciliation. Numerical simulations show that the HLA-involved scheme can compensate for the detriment of thermal noise and hence increase the security threshold of TS-CVQKD. In near-and-mid infrared band, security threshold can be extended by 2.1 dB in channel loss for direct reconciliation and 1.6 dB for reverse reconciliation, whereas in terahertz band, security threshold can be slightly enhanced for the gain parameter less than 1 due to the rise in thermal noise.

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Enhancing Phase Sensitivity in Mach–Zehnder Interferometers for Arbitrary Input States

Liang¹,

Pei²,

Wang³

2020

Chinese Phys. Lett.

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To enhance the phase sensitivity of Mach–Zehnder interferometers, we use a tunable phase shift before the light beams are injected into the interferometer. The analytical result of the optimal phase shift is obtained, which only depends on the initial input states. For a non-zero optimal phase shift, the phase sensitivity of the interferometers in the output ports is always enhanced. We can achieve this enhancement for most states, including entangled and mixed states. The optimal phase shift is exhibited in three examples. Compared to previous methods, this scheme provides a general way to improve phase sensitivity and could find wide applications in optical phase estimations.

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Temperature effects on atmospheric continuous-variable quantum key distribution*

Cited by 3 publications

References 27 publications

Performance analysis of quantum key distribution using polarized coherent-states in free-space channel

Performance analysis of quantum key distribution using polarized coherent-states in free-space channel

Hybrid linear amplifier-involved detection for continuous variable quantum key distribution with thermal states*

Enhancing Phase Sensitivity in Mach–Zehnder Interferometers for Arbitrary Input States

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