Characterizing the dynamics of quantum discord under phase damping with POVM measurements |
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Jiang Feng-Jian†
 , Jian-Feng Ye, Yan Xin-Hu, Lü Hai-Jiang‡ |
| For a fixed E , a moving point A corresponds to the ρ A along the z axis by LFO. Blue dashed line and black real line represent two functions of and respectively. The two functions intersecting at the point N make . One can draw a tangent line with zT ∈ ( zΔ , zG ), in which the average entropy can access a smaller value than that given by and corresponding to the dashed blue and real black lines. (b) In the PD channel, the shrinking E will make the value of the function increase. From top to bottom, three real black lines corresponding to different evolution time t 0 + δt , t 0 and t 0 − δ t show that the increases continuously for a certain z -axis coordinate z T of the local state. For a certain point (0, z T ) of the local state, A 1, A 2, and A 3 respectively correspond to optimal average entropy of different time instants of decoherence evolution under the POVM measurements. |
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