461 research outputs found
Twisted reduction in large N QCD with adjoint Wilson fermions
The twisted space-time reduced model of large QCD with various flavours
of adjoint Wilson fermions is constructed applying the symmetric twist boundary
conditions with flux . The models with one and two flavours show distinctive
behaviours. For the two flavor case, the string tension, calculated at ,
approaches zero as we decrease the quark mass in a way consistent with the
theory being governed by an infrared fixed point. In contrast, the string
tension for the case of a single adjoint Wilson fermion remains finite as the
quark mass decreases to zero, supporting that this is a confining theory.Comment: 7 pages, 8 figures, presented at the 31st International Symposium on
Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, German
The string tension from smeared Wilson loops at large N
We present the results of a high statistics analysis of smeared Wilson loops
in 4 dimensional SU(N) Yang-Mills theory for various values of N. The data is
used to analyze the behaviour of smeared Creutz ratios, extracting from them
the value of the string tension and other asymptotic parameters. A scaling
analysis allows us to extrapolate to the continuum limit for N=3,5,6 and 8. The
results are consistent with a approach towards the large N limit. The
same analysis is done for the TEK model (one-point lattice) for N=841 and a
non-minimal symmetric twist with flux of . The results match perfectly
with the extrapolated large N values, confirming the validity of the reduction
idea for this range of parameters.Comment: Enlarged revised version with 2 tables and 3 figure
The string tension for Large N gauge theory from smeared Wilson loops
Using smeared Creutz ratios we extract the string tension for SU(N) pure
gauge theory and =3,4,5,6,8. We employ these results to extrapolate to large
N. The same methodology is applied to the single-site Twisted Eguchi Kawai
model. The corresponding string tension matches perfectly within errors with
the extrapolated one, providing strong evidence in favour of the twisted
reduction framework. Interesting results are also obtained on the behaviour of
Creutz ratios for large sizes.Comment: 7 pages and 3 figures. Contribution to Lattice 2012 in Cairn
Large N meson masses from a matrix model
We explain how to compute meson masses in the large limit using the
twisted Eguchi-Kawai model. A very simple formula is derived, and we show how
it leads in a fast and efficient way to results which are in fairly good
agreement with other determinations. The method is easily extensible to reduced
models with dynamical fermions based on the twisted reduction idea.Comment: latex 14 pages and 3 figure
Perturbative contributions to Wilson loops in twisted lattice boxes and reduced models
We compute the perturbative expression of Wilson loops up to order for
SU() lattice gauge theories with Wilson action on a finite box with twisted
boundary conditions. Our formulas are valid for any dimension and any
irreducible twist. They contain as a special case that of the 4-dimensional
Twisted Eguchi-Kawai model for a symmetric twist with flux . Our results
allow us to analyze the finite volume corrections as a function of the flux. In
particular, one can quantify the approach to volume independence at large
as a function of flux . The contribution of fermion fields in the adjoint
representation is also analyzed.Comment: pdflatex 57 pages, 9 figures, 4 appendice
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