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arXiv · 2512.11224

Enhancing Long-distance Continuous-variable Quantum-key-distribution with an Error-correcting Relay

S. Nibedita Swain·Ryan J. Marshman·Josephine Dias·Alexander S. Solntsev·Timothy C. Ralph
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Abstract

Noiseless linear amplifiers (NLAs) serve as an effective means to enable long-distance continuous-variable (CV) quantum key distribution (QKD), even under realistic conditions with non-unit reconciliation efficiency. Separately, unitary averaging has been suggested to mitigate some stochastic noise, including phase noise in continuous-variable states. In this work, we combine these two protocols to simultaneously compensate for thermal-loss effects and suppress phase noise, thereby enabling long-distance CV QKD that surpasses the repeaterless bound, the fundamental rate-distance limit, for repeaterless quantum communication systems.

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S. Nibedita Swain, Ryan J. Marshman, Josephine Dias, Alexander S. Solntsev, Timothy C. Ralph. 2025-12-12. Enhancing Long-distance Continuous-variable Quantum-key-distribution with an Error-correcting Relay. https://arxiv.org/abs/2512.11224

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