5,632 research outputs found
Interactive Extraction of High-Frequency Aesthetically-Coherent Colormaps
Color transfer functions (i.e. colormaps) exhibiting a high frequency luminosity component have proven to be useful in the visualization of data where feature detection or iso-contours recognition is essential. Having these colormaps also display a wide range of color and an aesthetically pleasing composition holds the potential to further aid image understanding and analysis. However producing such colormaps in an efficient manner with current colormap creation tools is difficult. We hereby demonstrate an interactive technique for extracting colormaps from artwork and pictures. We show how the rich and careful color design and dynamic luminance range of an existing image can be gracefully captured in a colormap and be utilized effectively in the exploration of complex datasets
Heavy meson interquark potential
The resolution of Dyson-Schwinger equations leads to the freezing of the QCD
running coupling (effective charge) in the infrared, which is best understood
as a dynamical generation of a gluon mass function, giving rise to a momentum
dependence which is free from infrared divergences. We calculate the interquark
potential for heavy mesons by assuming that it is given by a massive One Gluon
Exchange potential and compare with phenomenologyical fits inspired by lattice
QCD. We apply these potential forms to the description of quarkonia and
conclude that, even though some aspects of the confinement mechanism are absent
in the Dyson Schwinger formalism, the results for the spectrum are surprisingly
accurate. We discuss explanations for this outcome.Comment: 13 pages and 6 figure
- Glueball Spectrum within a Constituent Picture
The quantum numbers and mass hierarchy of the glueballs observed in
-dimensional lattice QCD with gauge group SU() are shown to be in
agreement with a constituent picture. The agreement is maintained when going
from glueballs to gluelumps, and when the gauge group SO() is taken
instead of SU()
String deformations induced by retardation effects
The rotating string model is an effective model of mesons, in which the quark
and the antiquark are linked by a straight string. We previously developed a
new framework to include the retardation effects in the rotating string model,
but the string was still kept straight. We now go a step further and show that
the retardation effects cause a small deviation of the string from the straight
line. We first give general arguments constraining the string shape. Then, we
find analytical and numerical solutions for the string deformation induced by
retardation effects. We finally discuss the influence of the curved string on
the energy spectrum of the model.Comment: 3 figure
The Boltzmann Equation in Classical Yang-Mills Theory
We give a detailed derivation of the Boltzmann equation, and in particular
its collision integral, in classical field theory. We first carry this out in a
scalar theory with both cubic and quartic interactions and subsequently in a
Yang-Mills theory. Our method is not relied on a doubling of the fields, rather
it is based on a diagrammatic approach representing the classical solution to
the problem.Comment: 24 pages, 7 figures; v2: typos corrected, reference added, published
in Eur. Phys. J.
Constituent gluon interpretation of glueballs and gluelumps
Arguments are given that support the interpretation of the lattice QCD
glueball and gluelump spectra in terms of bound states of massless constituent
gluons with helicity-1. In this scheme, the mass hierarchy of the currently
known gluelumps and glueballs is mainly due to the number of constituent gluons
and can be understood within a simple flux tube model. It is also argued that
the lattice QCD glueball should be seen as a four-gluon bound state.
The flux tube model allows for a parameter-free computation of its mass, which
is in good agreement with lattice QCD.Comment: 3 figures, use of package youngta
Influence of the sample geometry on the vortex matter in superconducting microstructures
The dependence of the vortex penetration and expulsion on the geometry of
mesoscopic superconductors is reported. Hall magnetometry measurements were
performed on a superconducting Al square and triangle. The stability of the
vortex patterns imposed by the sample geometry is discussed. The
field-temperature diagram has been reconstructed showing the transitions
between states with different vorticity. We have found that the vortex
penetration is only weakly affected by the vortex configuration inside the
sample while the expulsion is strongly controlled by the stability of the
vortex patterns. A qualitative explanation for this observation is given.Comment: 6 pages, 4 figures, accepted for publication in Phys. Rev.
Moments of Angular Distribution in Two Mesons Photoproduction
The formalism devoted to the production of two pseudoscalar mesons with a
linearly polarized photon beam has been detailed and illustrated in Phys. Rev.
D100 (2019) 054017. This document reports the necessary formulas, without
proof, to perform an analysis of the angular distribution of two mesons
photoproduction. The relations to extract moments of the angular distribution
are provided, as well as the relations between moments and partial waves for a
system involving , and waves. The expressions of the integrated beam
asymmetry and the beam asymmetry along the axis in term of moments are
mentioned.Comment: 9 pages, 1 figures, MENU 2019 conference proceeding
Multiple phase slips phenomena in mesoscopic superconducting rings
We investigate the behavior of a mesoscopic one-dimensional ring in an
external magnetic field by simulating the time dependent Ginzburg-Landau
equations with periodic boundary conditions. We analyze the stability and the
different possible evolutions for the phase slip phenomena starting from a
metastable state. We find a stability condition relating the winding number of
the initial solution and the number of flux quanta penetrating the ring. The
analysis of multiple phase slips solutions is based on analytical results and
simulations. The role of the ratio of two characteristic times u is studied for
the case of a multiple phase slips transition. We found out that if u>>1,
consecutive multiple phase slips will be more favorable than simultaneous ones.
If u>1 is often a necessary
condition to reach the ground state. The influence of the Langevin noise on the
kinetics of the phase transition is discussed.Comment: 8 pages, 6 figure
- âŠ