Pairwise entanglement in symmetric multi-qubit systems
Pairwise entanglement in symmetric multi-qubit systems
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DOI：
10.1140/epjd/e20020045
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发表时间：
2001-06
期刊：
影响因子：
--
通讯作者：
Xiaoguang Wang;K. Mølmer
中科院分区：
文献类型：
--
作者：
Xiaoguang Wang;K. Mølmer
For pairs of particles extracted from a symmetric state ofNtwo-level systems, the two-particle density matrix is expressed in terms of expectation values of collective spin operators \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} for the large system. Results are presented for experimentally relevant examples of pure states: Dicke states |S,M>, spin coherent, and spin squeezed states, where only the symmetric subspace,S=N/2 is populated, and for thermally entangled mixed states populating also lowerSvalues. The entanglement of the extracted pair is then quantified by a calculation of the concurrence, which provides directly the entanglement of formation of the pair.
For pairs of particles extracted from a symmetric state ofNtwo-level systems, the two-particle density matrix is expressed in terms of expectation values of collective spin operators \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} for the large system. Results are presented for experimentally relevant examples of pure states: Dicke states |S,M>, spin coherent, and spin squeezed states, where only the symmetric subspace,S=N/2 is populated, and for thermally entangled mixed states populating also lowerSvalues. The entanglement of the extracted pair is then quantified by a calculation of the concurrence, which provides directly the entanglement of formation of the pair.