关键词: 自由空间量子通信/
非球形气溶胶粒子/
大气相对湿度/
纠缠度
English Abstract
Influences of nonspherical aerosol particles and relative humidity of atmosphere on the performance of free space quantum communication
Nie Min1,Ren Jia-Ming1,
Yang Guang1,2,
Zhang Mei-Ling1,
Pei Chang-Xing3
1.School of Communication and Information Engineering, Xi'an University of Posts and Telecommunication, Xi'an 710121, China;
2.School of Electronics and Information, Northwestern Polytechnical University, Xi'an 710072, China;
3.State Key Laboratory of Integrated Service Networks, Xi'an University of Electronic Science and Technology, Xi'an 710071, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61172071, 61201194), the Natural Science Research Foundation of Shaanxi Province, China (Grant No. 2014JQ8318) and the International Scientific and Technological Cooperation and Exchange Program in Shaanxi Province, China (Grant No. 2015KW-013).Received Date:20 March 2016
Accepted Date:20 May 2016
Published Online:05 October 2016
Abstract:When the optical signal is transmitted in the free space, it inevitably passes through the atmosphere. The atmospheric aerosol is one of the most important components of the atmosphere, which not only affects the regional climate, but also influences the transmission of the free space optical signal. However, the study on the relationship between the non-spherical aerosols and the parameters of the free space quantum communication channel has not been carried out so far. To investigate this relationship, the spectral distribution function of the aerosol and its extinction factor should be analyzed first. According to three nonspherical aerosol particles: cylindrical particles, ellipsoidal particles and Chebyshev particles, the equation between channel attenuation of the free space quantum communication and the degree of quantum entanglement can then be established. After that, the effects of the relative humidity of the atmosphere on the degree of quantum entanglement and the fidelity of quantum communication can be analyzed and simulated finally. The simulation results show that the channel attenuations of the free space quantum communication are sequenced in ascending order as cylindrical particles, ellipsoidal particles, and Chebyshev particles, and their influences on the degree of quantum entanglement have different changing trends. When the transmission time is fixed, with the increase of aspect ratio of ellipsoidal particles, the degree of quantum entanglement shows a growing trend, with the increase of aspect ratio of cylindrical particles, the degree of quantum entanglement shows descending trend. With the increase of Chebyshev particle equivalent radius, the degree of quantum entanglement also shows the descending trend. When the relative humidity of the atmosphere is 0.2(0.9), the degree of quantum entanglement and the fidelity of quantum communication will be 0.72(0.75) and 0.32(0.22), respectively. It can be seen that the nonspherical aerosol particles and the relative humidity of the atmosphere each have a significant effect on the function of the free space quantum communication system. Therefore, in a practical free space quantum communication system, the shape factor of nonspherical aerosol particle, orientating factor, equivalent radius and the relative humidity of the atmosphere cannot be ignored, in order to improve the effectiveness and reliability of the free space quantum communication, the different parameters of the communication system should be adjusted adaptively.
Keywords: free space quantum communication/
non spherical aerosol particles/
relative humidity of the atmosphere/
degree of quantum entanglement
