36,121 research outputs found
The gluon propagator from large asymmetric lattices
The Landau-gauge gluon propagator is computed for the SU(3) gauge theory on
lattices up to a size of . We use the standard Wilson action
at and compare our results with previous computations using large
asymmetric and symmetric lattices. In particular, we focus on the impact of the
lattice geometry and momentum cuts to achieve compatibility between data from
symmetric and asymmetric lattices for a large range of momenta.Comment: Poster presented at Lattice2007, Regensburg, July 30 - August 4, 200
Are the Tails of Percolation Thresholds Gaussians ?
The probability distribution of percolation thresholds in finite lattices
were first believed to follow a normal Gaussian behaviour. With increasing
computer power and more efficient simulational techniques, this belief turned
to a stretched exponential behaviour, instead. Here, based on a further
improvement of Monte Carlo data, we show evidences that this question is not
yet answered at all.Comment: 7 pages including 3 figure
Atividade da peroxidase em linhagens de milho resistentes e susceptíveis ao mosaico causado por potyvirus.
xEdição dos resumos do 32º Congresso Brasileiro de Fitopatologia, Curitiba, 1999
Complete high-precision entropic sampling
Monte Carlo simulations using entropic sampling to estimate the number of
configurations of a given energy are a valuable alternative to traditional
methods. We introduce {\it tomographic} entropic sampling, a scheme which uses
multiple studies, starting from different regions of configuration space, to
yield precise estimates of the number of configurations over the {\it full
range} of energies, {\it without} dividing the latter into subsets or windows.
Applied to the Ising model on the square lattice, the method yields the
critical temperature to an accuracy of about 0.01%, and critical exponents to
1% or better. Predictions for systems sizes L=10 - 160, for the temperature of
the specific heat maximum, and of the specific heat at the critical
temperature, are in very close agreement with exact results. For the Ising
model on the simple cubic lattice the critical temperature is given to within
0.003% of the best available estimate; the exponent ratios and
are given to within about 0.4% and 1%, respectively, of the
literature values. In both two and three dimensions, results for the {\it
antiferromagnetic} critical point are fully consistent with those of the
ferromagnetic transition. Application to the lattice gas with nearest-neighbor
exclusion on the square lattice again yields the critical chemical potential
and exponent ratios and to good precision.Comment: For a version with figures go to
http://www.fisica.ufmg.br/~dickman/transfers/preprints/entsamp2.pd
Peroxidase activity and isoenzyme pattern in maize inbred lines contrasting in their resistance to potyvirus-induced-mosaic.
Universal features and tail analysis of the order-parameter distribution of the two-dimensional Ising model: An entropic sampling Monte Carlo study
We present a numerical study of the order-parameter probability density
function (PDF) of the square Ising model for lattices with linear sizes
. A recent efficient entropic sampling scheme, combining the
Wang-Landau and broad histogram methods and based on the high-levels of the
Wang-Landau process in dominant energy subspaces is employed. We find that for
large lattices there exists a stable window of the scaled order-parameter in
which the full ansatz including the pre-exponential factor for the tail regime
of the universal PDF is well obeyed. This window is used to estimate the
equation of state exponent and to observe the behavior of the universal
constants implicit in the functional form of the universal PDF. The probability
densities are used to estimate the universal Privman-Fisher coefficient and to
investigate whether one could obtain reliable estimates of the universal
constants controlling the asymptotic behavior of the tail regime.Comment: 24 pages, 5 figure
The low dimensional dynamical system approach in General Relativity: an example
In this paper we explore one of the most important features of the Galerkin
method, which is to achieve high accuracy with a relatively modest
computational effort, in the dynamics of Robinson-Trautman spacetimes.Comment: 7 pages, 5 figure
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