Figure 2
(a) The relative lower bound of 
and (b) the upper bound of 
for different photon sources. The solid lines (W0) represent the results of using infinite-decoy state method and the dashed or dotted lines (W1, P1 or S1) represent using three-decoy state method. Besides, W, P or S each corresponds to the scheme of using weak coherent sources38, possonian heralded single photon sources15 or sub-possonian heralded single photon sources42, individually. Here the superscript X represents in X basis and at each point, we set μ = 0.05 and optimize the value for μ′.
