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‡ |
| (a) An E shrinks to z axis under the PD channels, and the E of the dashed line corresponds to the shrinking ellipse. Points G , E ( E ′), and F ( F ′) represent the decomposed states respectively corresponding to a fixed point A under the POVM measurements. (b) Plot of the evolution of quantum and classical correlations of the X state with matrix elements ρ 11 = 0.4875, ρ 22 = 0.1625, ρ 33 = 0.0875, ρ 44 = 1 – ρ 11 – ρ 22 – ρ 33, ρ 23 = 0.1118, and ρ 14 = 0.3354. The red and blue lines respectively correspond to classical and quantum decoherences. The time instant of γC ( t 0) ≈ 0.4734 corresponding to the sudden change point as the result of the two-element orthogonal measurements can make . The embedded figure shows clearly that there is no sudden change point due to the optimization procedure of three-element POVM measurements. (c) Adopting the POVM optimization, the point can decrease continuously from point A to lower vertex H with the shrinking E . |
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