17,713 research outputs found

    Complete Study of Hadroproduction of a Υ\Upsilon Meson Associated with a Prompt J/ψJ/\psi

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    We present the first complete study of Υ\Upsilon and prompt J/ψJ/\psi production from single-parton scattering, including the complete O(αS6)\mathcal{O}(\alpha_S^6) color-singlet contribution, the O(αS2α2)\mathcal{O}(\alpha_S^2\alpha^2) electroweak contribution, the complete nonrelativistic S-wave and P-wave color-octet contribution as well as the feeddown contribution. Our study was motivated by the recent evidence reported by D0 Collaboration of prompt J/ψJ/\psi and Υ\Upsilon simultaneous production at the Tevatron. With our complete evaluation, we are able to refine the determination of the double parton scattering contribution made by D0 Collaboration. We find that the effective cross section characterizing the importance of double-parton scatterings is σeff≤8.2\sigma_{\rm eff}\le 8.2 mb at 68%68\% confidence level from the D0 measurement.Comment: 11 pages, 4 figures, 4 tables; v2: journal version, update the references and fix a few typo

    Non-classicalities via perturbing local unitary operations

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    We study the nonclassical correlations in a two-qubit state by the perturbing local unitary operation method. We find that the definitions of various non-classicalities including quantum discord (QD), measurement-induced nonlocality (MIN) and so on usually do not have a unique definition when expressed as the perturbation of local unitary operations, so a given non-classicality can lead to different definitions of its dual non-classicality. In addition, it is shown that QD and MIN are not the corresponding dual expressions in a simple set of unitary operations, even though they are in their original definitions. In addition, we also consider the non-classicalities in general 2⊗d2\otimes d dimensional systems

    The roles of quantum correlations in quantum cloning

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    In this paper, we study the entanglement and quantum discord of the output modes in the unified 1→21\rightarrow 2 state-dependent cloning and probabilistic quantum cloning. The tripartite entanglement among the output modes and the quantum cloning machine is also considered. We find that the roles of the quantum correlations including the bipartite and tripartite entanglement and quantum discord strongly depend on the quantum cloning machines as well as the cloned state. In particular, it is found that this quantum cloning scheme can be realizable even without any quantum correlation.Comment: Accepted by Eur. Phys. J.

    Multi-Source Multi-View Clustering via Discrepancy Penalty

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    With the advance of technology, entities can be observed in multiple views. Multiple views containing different types of features can be used for clustering. Although multi-view clustering has been successfully applied in many applications, the previous methods usually assume the complete instance mapping between different views. In many real-world applications, information can be gathered from multiple sources, while each source can contain multiple views, which are more cohesive for learning. The views under the same source are usually fully mapped, but they can be very heterogeneous. Moreover, the mappings between different sources are usually incomplete and partially observed, which makes it more difficult to integrate all the views across different sources. In this paper, we propose MMC (Multi-source Multi-view Clustering), which is a framework based on collective spectral clustering with a discrepancy penalty across sources, to tackle these challenges. MMC has several advantages compared with other existing methods. First, MMC can deal with incomplete mapping between sources. Second, it considers the disagreements between sources while treating views in the same source as a cohesive set. Third, MMC also tries to infer the instance similarities across sources to enhance the clustering performance. Extensive experiments conducted on real-world data demonstrate the effectiveness of the proposed approach
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