Long-distance free-space quantum key distribution with continuous variables

Fuente: arXiv
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Autores principales: Zhan, Tianxiang, Li, Huasheng, Huang, Peng, Chen, Haoze, Han, Jiaqi, Wu, Zijing, Fang, Hao, Yin, Hanwen, Zhou, Zehao, Fu, Huiting, Ji, Feiyu, Tan, Piao, Zhou, Yingming, Jiang, Xueqin, Wang, Tao, Wu, Jincai, Ye, Cheng, Miao, Yajun, Qi, Wei, Zeng, Guihua
Formato: Preprint
Publicado: 2025
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author Zhan, Tianxiang
Li, Huasheng
Huang, Peng
Chen, Haoze
Han, Jiaqi
Wu, Zijing
Fang, Hao
Yin, Hanwen
Zhou, Zehao
Fu, Huiting
Ji, Feiyu
Tan, Piao
Zhou, Yingming
Jiang, Xueqin
Wang, Tao
Wu, Jincai
Ye, Cheng
Miao, Yajun
Qi, Wei
Zeng, Guihua
author_facet Zhan, Tianxiang
Li, Huasheng
Huang, Peng
Chen, Haoze
Han, Jiaqi
Wu, Zijing
Fang, Hao
Yin, Hanwen
Zhou, Zehao
Fu, Huiting
Ji, Feiyu
Tan, Piao
Zhou, Yingming
Jiang, Xueqin
Wang, Tao
Wu, Jincai
Ye, Cheng
Miao, Yajun
Qi, Wei
Zeng, Guihua
contents Continuous-variable quantum key distribution (CVQKD) enables remote users to share high-rate and unconditionally secure secret keys while maintaining compatibility with classical optical communication networks and effective resistance against background noise. However, CVQKD experiments have only been demonstrated indoors or over short outdoor distances. Here, by developing channel-fluctuation-independent high-precision manipulation of continuous-variable quantum states, high-accuracy quantum signal acquisition and processing, and high-efficiency free-space acquisition, tracking, and pointing technology, we overcome the excess noise due to atmospheric effects especially in daylight without extra wavelength conversion and spectral filtering, and demonstrate for the first time long-distance free-space quantum key distribution over 7-km inland and 9.6-km maritime atmospheric channels with Gaussian-modulated coherent states. This achieved distribution distance of secure quantum secret keys is well beyond the atmosphere's effective thickness, offering a promising alternative for realizing satellite-based quantum cryptography communication in daylight. Moreover, given that the CVQKD system is naturally compatible with existing ground fiber telecommunication networks, it marks an essential step for realizing integrated air-ground quantum access networks with cross-domain applications.
format Preprint
id arxiv_https___arxiv_org_abs_2507_21546
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Long-distance free-space quantum key distribution with continuous variables
Zhan, Tianxiang
Li, Huasheng
Huang, Peng
Chen, Haoze
Han, Jiaqi
Wu, Zijing
Fang, Hao
Yin, Hanwen
Zhou, Zehao
Fu, Huiting
Ji, Feiyu
Tan, Piao
Zhou, Yingming
Jiang, Xueqin
Wang, Tao
Wu, Jincai
Ye, Cheng
Miao, Yajun
Qi, Wei
Zeng, Guihua
Quantum Physics
Continuous-variable quantum key distribution (CVQKD) enables remote users to share high-rate and unconditionally secure secret keys while maintaining compatibility with classical optical communication networks and effective resistance against background noise. However, CVQKD experiments have only been demonstrated indoors or over short outdoor distances. Here, by developing channel-fluctuation-independent high-precision manipulation of continuous-variable quantum states, high-accuracy quantum signal acquisition and processing, and high-efficiency free-space acquisition, tracking, and pointing technology, we overcome the excess noise due to atmospheric effects especially in daylight without extra wavelength conversion and spectral filtering, and demonstrate for the first time long-distance free-space quantum key distribution over 7-km inland and 9.6-km maritime atmospheric channels with Gaussian-modulated coherent states. This achieved distribution distance of secure quantum secret keys is well beyond the atmosphere's effective thickness, offering a promising alternative for realizing satellite-based quantum cryptography communication in daylight. Moreover, given that the CVQKD system is naturally compatible with existing ground fiber telecommunication networks, it marks an essential step for realizing integrated air-ground quantum access networks with cross-domain applications.
title Long-distance free-space quantum key distribution with continuous variables
topic Quantum Physics
url https://arxiv.org/abs/2507.21546