Theory of atmospheric quantum channels based on the law of total probability
Theory of atmospheric quantum channels based on the law of total probability
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DOI：
10.1103/physreva.97.063852
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发表时间：
2018-03
影响因子：
2.9
通讯作者：
D. Vasylyev;W. Vogel;A. Semenov
中科院分区：
文献类型：
--
作者：
D. Vasylyev;W. Vogel;A. Semenov
大气湍流是影响传输光信号量子特性的主要因素，可能会严重影响量子通信协议的性能。自由空间信道的透过率概率分布是大气链路的主要特征。应用全概率定律，通过分离湍流引起的光束漂移和光斑扭曲的贡献，我们得到了PDT。因此，所得到的PDT从对数负的威布尔分布到截断的对数正态分布取决于信道特性。此外，我们还证明了该方法允许人们一致地描述光束跟踪，这是实际长距离自由空间量子通信中通常使用的过程。我们分析了诱饵态量子密钥交换在湍流大气中的安全性，表明光束跟踪并不总是提高量子通信的效率。
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 characteristic 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 improve quantum communication.