869 research outputs found
Effect of the Gribov horizon on the Polyakov loop and vice versa
We consider finite temperature SU(2) gauge theory in the continuum
formulation, which necessitates the choice of a gauge fixing. Choosing the
Landau gauge, the existing gauge copies are taken into account by means of the
Gribov-Zwanziger (GZ) quantization scheme, which entails the introduction of a
dynamical mass scale (Gribov mass) directly influencing the Green functions of
the theory. Here, we determine simultaneously the Polyakov loop (vacuum
expectation value) and Gribov mass in terms of temperature, by minimizing the
vacuum energy w.r.t. the Polyakov loop parameter and solving the Gribov gap
equation. Inspired by the Casimir energy-style of computation, we illustrate
the usage of Zeta function regularization in finite temperature calculations.
Our main result is that the Gribov mass directly feels the deconfinement
transition, visible from a cusp occurring at the same temperature where the
Polyakov loop becomes nonzero. In this exploratory work we mainly restrict
ourselves to the original Gribov-Zwanziger quantization procedure in order to
illustrate the approach and the potential direct link between the vacuum
structure of the theory (dynamical mass scales) and (de)confinement. We also
present a first look at the critical temperature obtained from the Refined
Gribov-Zwanziger approach. Finally, a particular problem for the pressure at
low temperatures is reported.Comment: 19 pages, 8 .pdf figures. v2: extended section 3 + extra references;
version accepted for publication in EPJ
Double non-perturbative gluon exchange: an update on the soft Pomeron contribution to pp scattering
We employ a set of recent, theoretically motivated, fits to non-perturbative
unquenched gluon propagators to check in how far double gluon exchange can be
used to describe the soft sector of pp scattering data (total and differential
cross section). In particular, we use the refined Gribov--Zwanziger gluon
propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and
the massive Cornwall-type gluon propagator (as motivated from Dyson-Schwinger
equations) in conjunction with a perturbative quark-gluon vertex, next to a
model based on the non-perturbative quark-gluon Maris-Tandy vertex, popular
from Bethe-Salpeter descriptions of hadronic bound states. We compare the cross
sections arising from these models with "older" ISR and more recent TOTEM and
ATLAS data. The lower the value of total energy \sqrt{s}, the better the
results appear to be.Comment: 14 pages, 8 .pdf figures. To appear in Phys.Rev.
El trigo en la ciudad de México. Industria y comercio de un cultivo importado (1521 - 1564)
Sin resume
Optical binding in nanoparticle assembly: Potential energy landscapes
Optical binding is an optomechanical effect exhibited by systems of micro- and nanoparticles, suitably irradiated with off-resonance laser light. Physically distinct from standing-wave and other forms of holographic optical traps, the phenomenon arises as a result of an interparticle coupling with individual radiation modes, leading to optically induced modifications to Casmir-Polder interactions. To better understand how this mechanism leads to the observed assemblies and formation of patterns in nanoparticles, we develop a theory in terms of optically induced energy landscapes exhibiting the three-dimensional form of the potential energy field. It is shown in detail that the positioning and magnitude of local energy maxima and minima depend on the configuration of each particle pair, with regards to the polarization and wave vector of the laser light. The analysis reveals how the positioning of local minima determines the energetically most favorable locations for the addition of a third particle to each equilibrium pair. It is also demonstrated how the result of such an addition subtly modifies the energy landscape that will, in turn, determine the optimum location for further particle additions. As such, this development represents a rigorous and general formulation of the theory, paving the way toward full comprehension of nanoparticle assembly based on optical binding
ASLP-MULAN: Audio speech and language processing for multimedia analytics
Our intention is generating the right mixture of audio, speech and language technologies with big data ones. Some audio, speech and language automatic technologies are available or gaining enough degree of maturity as to be able to help to this objective: automatic speech transcription, query by spoken example, spoken information retrieval, natural language processing, unstructured multimedia contents transcription and description, multimedia files summarization, spoken emotion detection and sentiment analysis, speech and text understanding, etc. They seem to be worthwhile to be joined and put at work on automatically captured data streams coming from several sources of information like YouTube, Facebook, Twitter, online newspapers, web search engines, etc. to automatically generate reports that include both scientific based scores and subjective but relevant summarized statements on the tendency analysis and the perceived satisfaction of a product, a company or another entity by the general population
Conversion of 3-amino-4-arylamino-1H-isochromen-1-ones to 1-arylisochromeno[3,4-d][1,2,3]triazol-5(1H)-ones : synthesis, spectroscopic characterization and the structures of four products and one ring-opened derivative
The authors thank 'Centro de Instrumentación CientÃfico-Técnica of Universidad de Jaén' for data collection. The authors thank Universidad de Ciencias Aplicadas y Ambientales (UDCA), Universidad Nacional de Colombia, the ConsejerÃa de Innovación, Ciencia y Empresa (Junta de AndalucÃa, Spain) and the Universidad de Jaén for financial support.An efficient synthesis of 1-arylÂisochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazoÂtization of 3-amino-4-arylÂamino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The molÂecules of 1-phenylÂisochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds, while the structures of 1-(2-methylÂphenÂyl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chloroÂphenÂyl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the molÂecules into simple chains, which are further linked into sheets by Ï€-stacking interÂactions in (II) but not in (III). In the structure of 1-(4-chloroÂphenÂyl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the molÂecules into sheets. When comÂpound (II) was exposed to a strong acid in methanol, quÂantiÂtative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hyÂdroxy-1-(2-methylÂphenÂyl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the molÂecules are linked by paired O—H⋯O hydrogen bonds to form centrosymmetric dimers.Publisher PDFPeer reviewe
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