Balancing four-state continuous-variable quantum key distribution with linear optics cloning machine
Wu Xiao-Dong1, Liao Qin1, Huang Duan1, 2, †, Wu Xiang-Hua1, Guo Ying1, 3, ‡
       

The EB scheme for the four-state CV-QKD protocol based on LOCM operation. (a) The four-state CV-QKD with LOCM in terms of two parameters λ and τ. (b) The equivalent four-state CV-QKD protocol with a thermal state of variance characterized by the tunable noise and transmittance .