Enhancing long-distance continuous-variable quantum key distribution with an error-correcting relay
Phys. Rev. A 114, 012625 – Published 29 July, 2026
DOI: https://doi.org/10.1103/r4pl-mgfy
Abstract
Noiseless linear amplifiers serve as an effective means to enable long-distance continuous-variable (CV) quantum key distribution (QKD), even under realistic conditions with nonunit 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.
