Figure 9
Relative difference between the noise reduction factor measured for high and low mean values of the thermal state as a function of the transmittance efficiency t. For all cases \(\langle m_{L} \rangle =0.1\). Black and purple solid lines correspond to \(\langle m_{H} \rangle =0.2\), blue and magenta dashed lines to \(\langle m_{H} \rangle =0.3\), and cyan and pink dotted lines to \(\langle m_{H} \rangle =0.4\). Black, blue and cyan lines refer to Eve, while purple, magenta, and pink to Bob. The vertical line corresponds to \(t=t^*\), that is the threshold value over which Bob measures \(R>1\).
