11,540 research outputs found

    Leptoquark patterns unifying neutrino masses, flavor anomalies, and the diphoton excess

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    Vector leptoquarks provide an elegant solution to a series of anomalies and at the same time generate naturally light neutrino masses through their mixing with the standard model Higgs boson. We present a simple Froggatt-Nielsen model to accommodate the B physics anomalies RKR_K and RDR_D, neutrino masses, and the 750750 GeV diphoton excess in one cohesive framework adding only two vector leptoquarks and two singlet scalar fields to the standard model field content.Comment: 12 pages, 10 figures; final version published in PR

    Influence of the Ambient Pressure on the Weld Quality for Magnetic Pulse Welded Sheet Joints

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    This paper examines the effect of reduced ambient pressure during the welding process on the quality of magnetic pulse weld seams. For this purpose, a specifically developed vacuum chamber was applied, which enables a reproducible implementation. This, in turn, prepared the ground for a systematic examination of this promising process parameter. The tests focused on comparison of the weld seams realized with different currents and acceleration distances under atmospheric pressure and in the vacuum chamber. Here, both similar (EN AW-1050-H14) and dissimilar material combinations were considered (EN AW-1050A-H14 + S235JR; EN-AW 6016-T6 + DC04). The evaluation criteria for the quality of the welds were the tensile strength of the joint and the size of the weld seam

    Positivity of relative canonical bundles and applications

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    Given a family f:XSf:\mathcal X \to S of canonically polarized manifolds, the unique K\"ahler-Einstein metrics on the fibers induce a hermitian metric on the relative canonical bundle KX/S\mathcal K_{\mathcal X/S}. We use a global elliptic equation to show that this metric is strictly positive on X\mathcal X, unless the family is infinitesimally trivial. For degenerating families we show that the curvature form on the total space can be extended as a (semi-)positive closed current. By fiber integration it follows that the generalized Weil-Petersson form on the base possesses an extension as a positive current. We prove an extension theorem for hermitian line bundles, whose curvature forms have this property. This theorem can be applied to a determinant line bundle associated to the relative canonical bundle on the total space. As an application the quasi-projectivity of the moduli space Mcan\mathcal M_{\text{can}} of canonically polarized varieties follows. The direct images RnpfΩX/Sp(KX/Sm)R^{n-p}f_*\Omega^p_{\mathcal X/S}(\mathcal K_{\mathcal X/S}^{\otimes m}), m>0m > 0, carry natural hermitian metrics. We prove an explicit formula for the curvature tensor of these direct images. We apply it to the morphisms SpTSRpfΛpTX/SS^p \mathcal T_S \to R^pf_*\Lambda^p\mathcal T_{\mathcal X/S} that are induced by the Kodaira-Spencer map and obtain a differential geometric proof for hyperbolicity properties of Mcan\mathcal M_{\text{can}}.Comment: Supercedes arXiv:0808.3259v4 and arXiv:1002.4858v2. To appear in Invent. mat

    Lagrangian tracers on a surface flow: the role of time correlations

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    Finite time correlations of the velocity in a surface flow are found to be important for the formation of clusters of Lagrangian tracers. The degree of clustering characterized by the Lyapunov spectrum of the flow is numerically shown to be in qualitative agreement with the predictions for the white-in-time compressible Kraichnan flow, but to deviate quantitatively. For intermediate values of compressibility the clustering is surprisingly weakened by time correlations.Comment: 4 pages, 5 figures, to be published in PR

    Analysis of the Weld Seam Area of Magnetic Pulse Welded Aluminium-Steel-Sheet-Connections on its Suitability as a Sign of Quality

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    This paper deals with the characterisation of the weld seam area of magnetic pulse welded aluminium-steel-sheet-connections for different material combinations and its suitability as a sign of quality. The goal of this work is to suggest a relationship between the weld seam area and the strength of the generated joint. Based on the results of this work, the weld seam area could be established as a basis of design and for dimensioning the magnetic pulse welded hybrid joints. To identify the correlation of the generated weld seam area with the maximum tensile force of the welded samples, several aluminium-steel-joints were welded and tested using tensile shear test. Thereafter, the weld seam area was measured and correlated to the maximum bearable tensile force of the joint. The tested material combinations were EN AW-1050A-H14 / S235JR and EN AW-6016-T6 / HCT780X. The results illustrate a positive linear correlation between the weld seam area of the joint and the maximum tensile force. At the same time further weld seam irregularities were identified which have to be considered for evaluating the suitability of the weld seam area as a sign of quality. Additionally, in order to prevent such irregularities or to ensure a good weld seam, the non-destructive testing method of active thermography is presented

    Qubit Channels Can Require More Than Two Inputs to Achieve Capacity

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    We give examples of qubit channels that require three input states in order to achieve the Holevo capacity.Comment: RevTex, 5 page, 4 figures

    The reduction of the closest disentangled states

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    We study the closest disentangled state to a given entangled state in any system (multi-party with any dimension). We obtain the set of equations the closest disentangled state must satisfy, and show that its reduction is strongly related to the extremal condition of the local filtering on each party. Although the equations we obtain are not still tractable, we find some sufficient conditions for which the closest disentangled state has the same reduction as the given entangled state. Further, we suggest a prescription to obtain a tight upper bound of the relative entropy of entanglement in two-qubit systems.Comment: a crucial error was correcte

    Compressibility of Mixed-State Signals

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    We present a formula that determines the optimal number of qubits per message that allows asymptotically faithful compression of the quantum information carried by an ensemble of mixed states. The set of mixed states determines a decomposition of the Hilbert space into the redundant part and the irreducible part. After removing the redundancy, the optimal compression rate is shown to be given by the von Neumann entropy of the reduced ensemble.Comment: 7 pages, no figur
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