11,540 research outputs found
Leptoquark patterns unifying neutrino masses, flavor anomalies, and the diphoton excess
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 and , neutrino masses, and
the 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
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
Given a family of canonically polarized manifolds, the
unique K\"ahler-Einstein metrics on the fibers induce a hermitian metric on the
relative canonical bundle . We use a global elliptic
equation to show that this metric is strictly positive on , 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 of canonically polarized varieties
follows.
The direct images , , carry natural hermitian metrics. We prove an
explicit formula for the curvature tensor of these direct images. We apply it
to the morphisms that are induced by the Kodaira-Spencer map and obtain a differential
geometric proof for hyperbolicity properties of .Comment: Supercedes arXiv:0808.3259v4 and arXiv:1002.4858v2. To appear in
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Lagrangian tracers on a surface flow: the role of time correlations
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
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
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
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
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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