Continuous-mode analysis of improved two-way CV-QKD
- URL: http://arxiv.org/abs/2601.19348v1
- Date: Tue, 27 Jan 2026 08:27:06 GMT
- Title: Continuous-mode analysis of improved two-way CV-QKD
- Authors: Yanhao Sun, Jiayu Ma, Xiangyu Wang, Song Yu, Ziyang Chen, Hong Guo,
- Abstract summary: Continuous-variable quantum key distribution (CV-QKD) enables information-theoretically secure key generation between legitimate parties.<n>An improved two-way CV-QKD protocol has been proposed, which exhibits increased robustness against excess noise.<n>We introduce temporal modes to characterize the evolution of optical fields in the improved two-way protocol.
- Score: 9.672673506875784
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Continuous-variable quantum key distribution (CV-QKD) enables information-theoretically secure key generation between legitimate parties. To further enhance system performance, an improved two-way CV-QKD protocol has been proposed, which is accessible in practice and exhibits increased robustness against excess noise. However, in practical implementations, device nonidealities inevitably drive the optical field from the single-mode regime into the continuous-mode regime. In this work, we introduce temporal modes to characterize the evolution of optical fields in the improved two-way protocol and establish a security analysis framework for the continuous-mode scenario based on adaptive normalization with calibrated shot-noise unit. In addition, finite-size effects are taken into account in the analysis. Our results demonstrate that the improved two-way protocol retains a performance advantage over one-way counterpart. The analysis provides useful guidance for the practical implementation and performance optimization of improved two-way CV-QKD systems.
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