Fast qubit-based frequency recovery algorithm for quantum key distribution

Fuente: arXiv
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Main Authors: Lu, Feng-Yu, Huang, Zheng-Kai, Deng, Jia-Jv, Zhang, Chi, Wang, Shuang, He, De-Yong, Yin, Zhen-Qiang, Chen, Wei, Guo, Guang-Can, Han, Zheng-Fu
Format: Preprint
Published: 2025
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author Lu, Feng-Yu
Huang, Zheng-Kai
Deng, Jia-Jv
Zhang, Chi
Wang, Shuang
He, De-Yong
Yin, Zhen-Qiang
Chen, Wei
Guo, Guang-Can
Han, Zheng-Fu
author_facet Lu, Feng-Yu
Huang, Zheng-Kai
Deng, Jia-Jv
Zhang, Chi
Wang, Shuang
He, De-Yong
Yin, Zhen-Qiang
Chen, Wei
Guo, Guang-Can
Han, Zheng-Fu
contents Clock synchronization serves as a foundational subsystem in quantum key distribution (QKD). The recently proposed Qubit-based synchronization (Qubit4Sync) has opportunities in eliminating additional cost, noise, and potential side channels. It offers a promising alternative to dedicated synchronization hardware. However, the current frequency recovery process in Qubit4Sync requires high data throughput and computational speed, limiting practical use. To overcome these issues, we developed a fast frequency recovery algorithm that increases the recovery rate by orders of magnitude and remains robust under bad signal-to-noise ratio (SNR). This enables Qubit4Sync to operate effectively in mainstream gated-mode QKD systems. We further establish a theoretical model for frequency recovery, showing that our algorithm is robust against disturbances like dead time, jitter, and afterpulse. A frequency-domain SNR calculation method is also provided to guide parameter design for specific experimental conditions. This work opens the door to practical Qubit4Sync deployment in general QKD systems.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17849
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast qubit-based frequency recovery algorithm for quantum key distribution
Lu, Feng-Yu
Huang, Zheng-Kai
Deng, Jia-Jv
Zhang, Chi
Wang, Shuang
He, De-Yong
Yin, Zhen-Qiang
Chen, Wei
Guo, Guang-Can
Han, Zheng-Fu
Quantum Physics
Clock synchronization serves as a foundational subsystem in quantum key distribution (QKD). The recently proposed Qubit-based synchronization (Qubit4Sync) has opportunities in eliminating additional cost, noise, and potential side channels. It offers a promising alternative to dedicated synchronization hardware. However, the current frequency recovery process in Qubit4Sync requires high data throughput and computational speed, limiting practical use. To overcome these issues, we developed a fast frequency recovery algorithm that increases the recovery rate by orders of magnitude and remains robust under bad signal-to-noise ratio (SNR). This enables Qubit4Sync to operate effectively in mainstream gated-mode QKD systems. We further establish a theoretical model for frequency recovery, showing that our algorithm is robust against disturbances like dead time, jitter, and afterpulse. A frequency-domain SNR calculation method is also provided to guide parameter design for specific experimental conditions. This work opens the door to practical Qubit4Sync deployment in general QKD systems.
title Fast qubit-based frequency recovery algorithm for quantum key distribution
topic Quantum Physics
url https://arxiv.org/abs/2509.17849