9,440 research outputs found
Schwinger-Dyson equations and the quark-antiquark static potential
In lattice QCD, a confining potential for a static quark-antiquark pair can
be computed with the Wilson loop technique. This potential, dominated by a
linear potential at moderate distances, is consistent with the confinement with
a flux tube, an extended and scalar system also directly observable in lattice
QCD. Quantized flux tubes have also been observed in another class of
confinement, the magnetic confinement in type II superconductors. On the other
hand the solution of Schwinger Dyson Equations, say with the Landau gauge
fixing and the truncation of the series of Feynman diagrams, already at the
rainbow level for the self energy and at the ladder level for the Bethe
Salpeter equation, provides a signal of a possible inverse quartic potential in
momentum space derived from one gluon and one ghost exchange, consistent with
confinement. Here we address the successes, difficulties and open problems of
the matching of these two different perspectives of confinement, the
Schwinger-Dyson perspective versus the flux tube perspective.Comment: 12 pages, 18 figures; talk presented at QCD-TNT, Trento, 7-11 sep
200
Gluons at finite temperature
The gluon propagator is investigated at finite temperature via lattice simulations. In particular, we discuss its interpretation as a massive-type bosonic propagator. Moreover, we compute the corresponding spectral density and study the violation of spectral positivity. Finally, we explore the dependence of the gluon propagator on the phase of the Polyakov loop
Sistemas diversificados com olerĂcolas em áreas de várzea alta do MunicĂpio de Iranduba-AM.
Realizou-se um inventário formal das práticas e tecnologias em uso por agricultores familiares de municĂpios circunvizinhos Ă capital do Estado, Manaus, grande centro demandador de alimentos, e neste trabalho, sĂŁo descritos sistemas diversificados com olerĂcolas, detectados em um dos municĂpios objeto de estudo, em ecossistema de várzea
Problemas fitossanitários e solução tecnológica na produção de cucurbitáceas por agricultores familiares do Estado do Amazonas.
O objetivo deste trabalho foi realizar um levantamento das doenças fúngicas e bacterianas incidentes sobre as cucurbitáceas cultivadas, e comentar as soluçções tecnológicas adotadas pelos agricultores, à luz de práticas agroecológicas. Adicionalmente, foram registrados aspectos relativos a insetos-pragas
The lattice gluon propagator in renormalizable gauges
We study the SU(3) gluon propagator in renormalizable gauges
implemented on a symmetric lattice with a total volume of (3.25 fm) for
values of the guage fixing parameter up to . As expected, the
longitudinal gluon dressing function stays constant at its tree-level value
. Similar to the Landau gauge, the transverse gauge gluon
propagator saturates at a non-vanishing value in the deep infrared for all
values of studied. We compare with very recent continuum studies and
perform a simple analysis of the found saturation with a dynamically generated
effective gluon mass.Comment: 6 pages, 4 figure
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