9,481 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
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
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
Circular No. 48, 1903. Oregon Short Line Railroad.
Circular concerning the annual meeting of the National Educational Association
Influence of symmetry and Coulomb-correlation effects on the optical properties of nitride quantum dots
The electronic and optical properties of self-assembled InN/GaN quantum dots
(QDs) are investigated by means of a tight-binding model combined with
configuration interaction calculations. Tight-binding single particle wave
functions are used as a basis for computing Coulomb and dipole matrix elements.
Within this framework, we analyze multi-exciton emission spectra for two
different sizes of a lens-shaped InN/GaN QD with wurtzite crystal structure.
The impact of the symmetry of the involved electron and hole one-particle
states on the optical spectra is discussed in detail. Furthermore we show how
the characteristic features of the spectra can be interpreted using a
simplified Hamiltonian which provides analytical results for the interacting
multi-exciton complexes. We predict a vanishing exciton and biexciton ground
state emission for small lens-shaped InN/GaN QDs. For larger systems we report
a bright ground state emission but with drastically reduced oscillator
strengths caused by the quantum confined Stark effect.Comment: 15 pages, 17 figure
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