6,198 research outputs found
Peeping into the SU(2) Gauge Vacuum
We study thermalised configurations of SU(2) gauge fields by cooling. An
analysis of the effect of cooling is presented and global and statistical
information is extracted.Comment: 3 pages, uuencoded compressed postscript file, contribution to LAT 9
Large reduction with the Twisted Eguchi-Kawai model
We examine the breaking of symmetry recently reported for the Twisted
Eguchi-Kawai model (TEK). We analyse the origin of this behaviour and propose
simple modifications of twist and lattice action that could avoid the problem.
Our results show no sign of symmetry breaking and allow us to obtain values of
the large infinite volume string tension in agreement with extrapolations
from results based upon straightforward methods.Comment: latex file 14 pages, 4 figure
Structure and evolution of strange attractors in non-elastic triangular billiards
We study pinball billiard dynamics in an equilateral triangular table. In
such dynamics, collisions with the walls are non-elastic: the outgoing angle
with the normal vector to the boundary is a uniform factor
smaller than the incoming angle. This leads to contraction in phase space for
the discrete-time dynamics between consecutive collisions, and hence to
attractors of zero Lebesgue measure, which are almost always fractal strange
attractors with chaotic dynamics, due to the presence of an expansion
mechanism. We study the structure of these strange attractors and their
evolution as the contraction parameter is varied. For in
the interval (0, 1/3), we prove rigorously that the attractor has the structure
of a Cantor set times an interval, whereas for larger values of the
billiard dynamics gives rise to nonaccessible regions in phase space. For
close to 1, the attractor splits into three transitive components,
the basins of attraction of which have fractal basin boundaries.Comment: 12 pages, 10 figures; submitted for publication. One video file
available at http://sistemas.fciencias.unam.mx/~dsanders
Real-time Quantum evolution in the Classical approximation and beyond
With the goal in mind of deriving a method to compute quantum corrections for
the real-time evolution in quantum field theory, we analyze the problem from
the perspective of the Wigner function. We argue that this provides the most
natural way to justify and extend the classical approximation. A simple
proposal is presented that can allow to give systematic quantum corrections to
the evolution of expectation values and/or an estimate of the errors committed
when using the classical approximation. The method is applied to the case of a
few degrees of freedom and compared with other methods and with the exact
quantum results. An analysis of the dependence of the numerical effort involved
as a function of the number of variables is given, which allow us to be
optimistic about its applicability in a quantum field theoretical context.Comment: 32 pages, 6 figure
Calorons on the lattice - a new perspective
We discuss the manifestation of instanton and monopole solutions on a
periodic lattice at finite temperature and their relation to the infinite
volume analytic caloron solutions with asymptotic non-trivial Polyakov loops.
As a tool we use improved cooling and twisted boundary conditions. Typically we
find 2Q lumps for topological charge Q. These lumps are BPS monopoles.Comment: Latex. 16 pages, 9 figure
Recent results on self-dual configurations on the torus
We review the recent progress on our understanding of self-dual SU(N)
Yang-Mills configurations on the torus.Comment: Latex 3 pages, 1 figure. Contribution to the Lat99 Proceeding
Relaciones privadas internacionales en el MERCOSUR y en la Unión Europea
Ponencia recogida en las actas de los Cursos de Derecho Internacional y Relaciones Internacionales de Vitoria-Gasteiz organizados por la Facultad de Derecho de la Universidad del País VascoSe analizan en los dos sistemas de integración: MERCOSUR y Unión Europea, las estructuras institucionales y normativas (dimensión jurídica general de la integración), los modelos de mercado integrado (dimensión económico-comercial) y los aspectos propios de las relaciones típicas de Derecho internacional privado afectadas (dimensión jurídica particular de las relaciones privadas internacionales).
También las libertades de circulación en el espacio integrado y los contratos internacionales como cauce jurídico de las relaciones de contenido patrimonialAre analyzed the institutional and regulatory structures (general legal dimension of integration), the integrated market models (economic-commercial dimension) and aspects of the typical international law relation affected private sector (private legal dimension of private international relations) in two integration systems MERCOSUR and European Union. Also the freedoms of movement in the integrated space and international contracts as a legal channel of relations of heritage conten
Gauge invariant structures and Confinement
By looking at cooled configurations on the lattice, we study the presence of
peaks in the action density, or its electric and magnetic components, in the
SU(2) gauge vacuum. The peaks are seen to be of instanton-like nature and their
number variation takes care of the drop in the string tension observed when
cooling. Possible explanations of this finding are analysed.Comment: uuencoded and compressed file of the Postcript file newpaper.ps,
fig1.ps,fig2.eps,fig3.ps and fig4.ps. 13 pages of text and 4 figures Style
modifications and misprints correcte
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