Quantitative entanglement witnesses

被引:181
作者
Eisert, J. [1 ]
Brandao, F. G. S. L.
Audenaert, K. M. R.
机构
[1] Univ London Imperial Coll Sci Technol & Med, Inst Math Sci, London SW7 2PE, England
[2] Univ London Imperial Coll Sci Technol & Med, Blackett Lab, QOLS, London SW7 2BW, England
关键词
D O I
10.1088/1367-2630/9/3/046
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Entanglement witnesses provide tools to detect entanglement in experimental situations without the need of having full tomographic knowledge about the state. If one estimates in an experiment an expectation value smaller than zero, one can directly infer that the state has been entangled, or specifically multi-partite entangled, in the first place. In this paper, we emphasize that all these tests-based on the very same data-give rise to quantitative estimates in terms of entanglement measures: 'If a test is strongly violated, one can also infer that the state was quantitatively very much entangled'. We consider various measures of entanglement, including the negativity, the entanglement of formation, and the robustness of entanglement, in the bipartite and multipartite setting. As examples, we discuss several experiments in the context of quantum state preparation that have recently been performed.
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页数:19
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