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SCIENCE CHINA Information Sciences, Volume 60 , Issue 5 : 052501(2017) https://doi.org/10.1007/s11432-016-9006-6

Quantifying quantum information resources: a numerical study

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  • ReceivedSep 30, 2016
  • AcceptedDec 17, 2016
  • PublishedMar 14, 2017

Abstract


Acknowledgment

Lixin HE acknowledges the support from Chinese National Fundamental Research Program (Grant No. 2011CB921200), National Natural Science Funds for Distinguished Young Scholars, and the Fundamental Research Funds for the Central Universities (Grant No. WK2470000006).

  • Figure 1

    Entanglement of 4-qubit permutation-invariant state, i.e., Eq. (14) mixed by $| S(4,1) \rangle$ and $| S(4,1) \rangle$. The analytical result is represented by solid line and the numerical result by open circles.

  • Figure 2

    Quantum discord of 4 and 5-qubit superpositions of two canonical orthonormal GHZ states as in (15). The 4-qubit numerical result is represented by open circles and the 5-qubit numerical result by crosses, compared to the analytical result represented by solid line.

  • Figure 3

    (Color online) Quantum discord of $3$ to $6$ qubit states (18) mixed by permutation-invariant states $| S(n,1) \rangle$ and $| S(n,1) \rangle$.

  • Figure 4

    (Color online) Quantum discord of 4-qubit mboxstates (19) mixed by $| S(4,1) \rangle$, $| S(4,1) \rangle$ and $| S(4,3) \rangle$, plotted on $\alpha$-$\beta$ plane.

  • Figure 5

    (Color online) Robustness of the turning point: Quantum discord of the original 4-qubit state in (19) when $\alpha=0$, and the states after tracing out one and two qubits from the original state. The turning point exists in all three states, showing its robustness.