1,396 research outputs found
Color Dynamics in External Fields
We investigate the vacuum dynamics of U(1), SU(2), and SU(3) lattice gauge
theories in presence of external (chromo)magnetic fields, both in (3+1) and
(2+1) dimensions. We find that the critical coupling for the phase transition
in compact U(1) gauge theory is independent of the strength of an external
magnetic field. On the other hand we find that, both in (3+1) and (2+1)
dimensions, the deconfinement temperature for SU(2) and SU(3) gauge systems in
a constant abelian chromomagnetic field decreases when the strength of the
applied field increases. We conclude that the dependence of the deconfinement
temperature on the strength of an external constant chromomagnetic field is a
peculiar feature of non abelian gauge theories and could be useful to get
insight into color confinement.Comment: 26 pages, 14 figure
Homo ludens-designing tomorrow's games
In an electronic and cybernetic world, when one is faced with the task of devising different kinds of interaction among participants, it is worth reflecting that, out of the many and various activities which people engage in, there is one kind of activity which has been cultivated, practised and performed for thousands of years by all members of society. This is the playing of games
QCD dynamics in a constant chromomagnetic field
We investigate the phase transition in full QCD with two flavors of staggered
fermions in presence of a constant abelian chromomagnetic field. We find that
the critical temperature depends on the strength of the chromomagnetic field
and that the deconfined phase extends to very low temperatures for strong
enough fields. As in the case of zero external field, a single transition is
detected, within statistical uncertainties, where both deconfinement and chiral
symmetry restoration take place. We also find that the chiral condensate
increases with the strength of the chromomagnetic field.Comment: 18 pages, 8 figures, 1 tabl
Probing the non-perturbative dynamics of SU(2) vacuum
The vacuum dynamics of SU(2) lattice gauge theory is studied by means of a
gauge-invariant effective action defined using the lattice Schr\"odinger
functional. Numerical simulations are performed both at zero and finite
temperature. The vacuum is probed using an external constant Abelian
chromomagnetic field. The results suggest that at zero temperature the external
field is screened in the continuum limit. On the other hand at finite
temperature it seems that confinement is restored by increasing the strength of
the applied field.Comment: 29 pages, 10 figures, LaTeX2
Modelling Discourse-related terminology in OntoLingAnnotâs ontologies
Recently, computational linguists have shown great interest in discourse annotation in an attempt to capture the internal relations in texts. With this aim, we have formalized the linguistic knowledge associated to discourse into different linguistic ontologies. In this paper, we present the most prominent discourse-related terms and concepts included in the ontologies of the OntoLingAnnot annotation model. They show the different units, values, attributes, relations, layers and strata included in the discourse annotation level of the OntoLingAnnot model, within which these ontologies are included, used and evaluated
The deconfining phase transition in full QCD with two dynamical flavors
We investigate the deconfining phase transition in SU(3) pure gauge theory
and in full QCD with two flavors of staggered fermions. The phase transition is
detected by measuring the free energy in presence of an abelian monopole
background field. In the pure gauge case our finite size scaling analysis is in
agreement with the well known presence of a weak first order phase transition.
In the case of 2 flavors full QCD we find, using the standard pure gauge and
staggered fermion actions, that the phase transition is consistent with weak
first order, contrary to the expectation of a crossover for not too large quark
masses and in agreement with results obtained by the Pisa group.Comment: 23 pages, 11 figures, 4 tables (minor typos corrected, references
updated, accepted for publication on JHEP
Magnetic Instability in a Parity Invariant 2D Fermion System
We consider the parity invariant (2+1)-dimensional QED where the matter is
represented as a mixture of fermions with opposite spins. It is argued that the
perturbative ground state of the system is unstable with respect to the
formation of magnetized ground state. Carrying out the finite temperature
analysis we show that the magnetic instability disappears in the high
temperature regime.Comment: 7 pages, RevTe
A gauge invariant study of the monopole condensation in non Abelian lattice gauge theories
We investigate the Abelian monopole condensation in finite temperature SU(2)
and SU(3) pure lattice gauge theories. To this end we introduce a gauge
invariant disorder parameter built up in terms of the lattice Schr\"odinger
functional. Our numerical results show that the disorder parameter is different
from zero and Abelian monopole condense in the confined phase. On the other
hand our numerical data suggest that the disorder parameter tends to zero, in
the thermodynamic limit, when the gauge coupling constant approaches the
critical deconfinement value. In the case of SU(3) we also compare the
different kinds of Abelian monopoles which can be defined according to the
choice of the Abelian subgroups.Comment: 18 pages, 7 figures, LaTe
Enriching Ontologies with Multilingual Information
Multilinguality in ontologies has become an impending need for institutions worldwide that have to deal with data and linguistic resources in different natural languages. Since most ontologies are developed in one language, obtaining multilingual ontologies implies to localize or adapt them to a concrete language and culture community. As the adaptation of the ontology conceptualization demands considerable efforts, we propose to modify the ontology terminological layer by associating an external repository of linguistic data to the ontology. With this aim we provide a model called Linguistic Information Repository (LIR) that associated to the ontology meta-model allows terminological layer localization
TerminologĂa, OntologĂas y Multilingualidad
La terminologĂa entendida como la descripciĂłn y la organizaciĂłn de los conceptos de un dominio de conocimiento, las relaciones entre los conceptos y los tĂ©rminos o las definiciones que denotan esos conceptos estĂĄn presentes en diferentes ĂĄmbitos. ..
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