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Advanced Quantum Technologies

Terahertz Continuous‐Variable Measurement‐Device‐Independent Quantum key Distribution with Photon Subtraction in Inter‐Satellite Links Communication

Chengji Liu, Zhe Xu, Xinyu Wan, Mengyao Hou, Lu Wang, Qingshan Li

Published Feb 24, 2025• 1 citation
Publisher

Abstract

Abstract Quantum communication in the terahertz (THz) band is an important technology for next‐generation high‐capacity wireless networks, and inter‐satellite quantum key distribution in low‐earth‐orbit (LEO) is one of the critical research directions. A terahertz continuous‐variable measurement‐device‐independent quantum key distribution (CV‐MDI‐QKD) with photon subtraction for secure inter‐satellite link communications, derive the security bounds for the protocol, is proposed and the performance of the inter‐satellite link in the asymptotic limit, in addition to obtaining a tighter protocol bound by considering finite size effects, is evaluated. Through simulation calculations, the method can maintain high secret key rates and robust security, which will provide a more effective way to build future quantum networks.

DOI
10.1002/qute.202400570

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We have introduced, for the first time, a protocol for Continuous-Variable Measurement-Device-Independent Quantum Key Distribution (CV-MDI-QKD) in the terahertz (THz) frequency band. We have conducted a secret key rate analysis against collective attacks. The proposed THz CV-MDI-QKD is immune to all detector attacks, significantly enhancing the security assurance of practical THz CVQKD implementations. Furthermore, we investigated the impact of finite key length (the finite-size effect) and finite reconciliation efficiency on the performance of practical THz CV-MDI-QKD systems. Our findings reveal that by employing a large number of keys or signals and optimizing the modulation variance, the detrimental effects arising from the finite-size effect and suboptimal reconciliation efficiency can be notably mitigated. These insights play a crucial role in advancing the feasibility of THz CVQKD technology towards practical applications.
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