Secret key rates of free-space optical continuous-variable quantum key distribution

Abstract

In this letter, we derive the maximal achievable secret key rates for continuous-variable quantum key distribution (CVQKD) over free-space optical (FSO) quantum channels. We provide a channel decomposition for FSO-CVQKD quantum channels and study the SNR (signal-to-noise ratio) characteristics. The analytical derivations focus particularly on the low-SNR scenarios. The results are convenient for wireless quantum key distribution and for the quantum Internet.