872 research outputs found

    Exactly Solvable Many-Body Systems and Pseudo-Hermitian Point Interactions

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    We study Hamiltonian systems with point interactions and give a systematic description of the corresponding boundary conditions and the spectrum properties for self-adjoint, PT-symmetric systems and systems with real spectra. The integrability of one dimensional many body systems with these kinds of point (contact) interactions are investigated for both bosonic and fermionic statistics.Comment: 7 page

    Measurable bounds for Entanglement of Formation

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    We study the entanglement of formation for arbitrary dimensional bipartite mixed unknown states. Experimentally measurable lower and upper bounds for entanglement of formation are derived.Comment: 9 pages, 4 figure

    On Locality of Schmidt-Correlated States

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    We review some results on the equivalence of quantum states under local unitary transformations (LUT). In particular, the classification of two-qubit Schmidt correlated (SC) states under LUT is investigated. By presenting the standard form of quantum states under LUT, the sufficient and necessary conditions of whether two different SC states are local unitary equivalent are provided. The correlations of SC states are also discussed.Comment: 14 page

    A Remark on the Optimal Cloning of An N-Level Quantum System

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    We study quantum cloning machines (QCM) that act on an unknown N-level quantum state and make M copies. We give a formula for the maximum of the fidelity of cloning and exhibit the unitary transformations that realize this optimal fidelity. We also extend the results to treat the case of M copies from NN^\prime (M>NM>N^\prime) identical N-level quantum systems.Comment: 8 pages, Late