Entangled three-qubit states without concurrence and three-tangle.
Entangled three-qubit states without concurrence and three-tangle.
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DOI：
10.1103/physrevlett.97.260502
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发表时间：
2006-06
影响因子：
8.6
通讯作者：
R. Lohmayer;A. Osterloh;J. Siewert;A. Uhlmann
中科院分区：
文献类型：
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作者：
R. Lohmayer;A. Osterloh;J. Siewert;A. Uhlmann
我们对由Greenberger-Horne-Zeilinger态和与之正交的W态组成的混合三量子比特态进行了完整的分析。我们提出了最佳分解和凸屋顶的三纠结。此外，我们提供了一个分析方法来决定是否有一个任意的三个量子比特的秩2状态有消失的三纠缠。这些结果突出了有趣的差异相比，两个量子比特的混合态的性质，并可能作为一个定量的参考，为未来的研究在多体混合态的纠缠。通过对Coffman-Kundu-Wootters不等式的研究，我们发现，虽然对于纯态，不等价纠缠类型的数量严格相加，但对于混合态，这种“一夫一妻制”可以通过消失的纠缠测度来解除。
We provide a complete analysis of mixed three-qubit states composed of a Greenberger-Horne-Zeilinger state and a W state orthogonal to the former. We present optimal decompositions and convex roofs for the three-tangle. Further, we provide an analytical method to decide whether or not an arbitrary rank-2 state of three qubits has vanishing three-tangle. These results highlight intriguing differences compared to the properties of two-qubit mixed states, and may serve as a quantitative reference for future studies of entanglement in multipartite mixed states. By studying the Coffman-Kundu-Wootters inequality we find that, while the amounts of inequivalent entanglement types strictly add up for pure states, this "monogamy" can be lifted for mixed states by virtue of vanishing tangle measures.