3,465 research outputs found
Are the low-momentum gluon correlations semiclassically determined?
We argue that low-energy gluodynamics can be explained in terms of
semi-classical Yang-Mills solutions by demonstrating that lattice gluon
correlation functions fit to instanton liquid predictions for low energies and,
after cooling, in the whole range.Comment: 4 pages, revtex
Non-relativistic bound states at finite temperature (II): the muonic hydrogen
We illustrate how to apply modern effective field theory techniques and
dimensional regularization to factorise the various scales which appear in QED
bound states at finite temperature. We focus here on the muonic hydrogen atom.
Vacuum polarization effects make the physics of this atom at finite temperature
very close to that of heavy quarkonium states. We comment on the implications
of our results for these states in the quark gluon plasma. In particular, we
estimate the effects of a finite charm quark mass in the dissociation
temperature of bottomonium.Comment: 22 pages, 8 figures. Journal version, reference adde
Advanced Pulse Coding Techniques for Distributed Optical Fiber Sensors
Advanced optical pulse coding methods to enhance the performance of distributed optical fiber sensors are reviewed. In particular, the latest implementations dedicated to high-performance long-range Raman and Brillouin based distributed sensing are described
Instanton traces in lattice gluon correlation functions
Strong coupling constant computed in Landau gauge and MOM renormalization
scheme from lattice two and three gluon Green Functions exhibits an unexpected
behavior in the deep IR, showing a maximum value around . We
analise this coupling below this maximum within a semiclassical approach, were
gluon degrees of freedom at very low energies are described in terms of the
classical solutions of the lagrangian, namely instantons. We provide some new
results concerning the relationship between instantons and the low energy
dynamics of QCD, by analising gluon two- and three-point Green functions
separately and with the help of a cooling procedure to eliminate short range
correlations.Comment: 4 pages, talk given at XXXX Rencontres de Moriond on QCD and Hadronic
Interactions, La Thuile (Italy
Modified instanton profile effects from lattice Green functions
We trace here instantons through the analysis of pure Yang-Mills gluon Green
functions in the Landau gauge for a window of IR momenta (0.4 GeV
GeV). We present lattice results that can be fitted only after substituting the
BPST profile in the Instanton liquid model (ILM) by one based on the Diakonov
and Petrov variational methods. This also leads us to gain information on the
parameters of ILM.Comment: 32 pagex, 6 figure
A Ghost Story II: Ghosts, Gluons and the Gluon condensate beyond the IR of QCD
Beyond the deep IR, the analysis of ghost and gluon propagators still keeps
very interesting non-perturbative information. The Taylor-scheme coupling can
be computed and applied to obtain the parameter from Landau
gauge lattice simulations. Furthermore, a dimension-two gluon condensate, that
can be understood in the instanton liquid model, plays an important role in the
game.Comment: 12 pp., 3 fig
Pratiques funéraires du second âge du Fer en Gaule de l'Ouest (Bretagne, Pays de la Loire, Poitou-Charentes)
International audienceHallstatt and La Tène funeraries practicies in Brittany, Loire countries and Western-Central FranceBilan des pratiques funéraires de l'Armorique au centre-Ouest de la France pendant le premier et le second âge du fe
An Instanton Picture O.P.E. <A^2> Condensate?
Gluon two- and three-point Green Functions computed in Landau gauge from the
lattice show the existence of power corrections to the purely perturbative
expressions, that can be explained through an Operator Product Expansion as the
influence of a non gauge invariant mass dimension two condensate. The
relationship of this condensate with topological properties of QCD, namely
instantons, will be studied, giving a first estimate of the contribution of
instantons to this condensate based in the direct lattice measure, after a
cooling process, of the instanton liquid properties.Comment: Lattice2002(topology) contribution, 3 pages, 2 figure
Novel Concepts and Recent Progress in Distributed Optical Fiber Sensing
Recent techniques open new perspectives for distributed fiber sensing. Pulse coding and multi-dimensional denoising methods result in a >10 dB noise reduction with minor modifications of the experimental layout
- …