Perturbative Aspects of the Deconfinement Transition
Résumé
In the case of non-abelian gauge theories, the standard FaddeevPopov gauge-fixing procedure in the Landau gauge is known to be incomplete due to the presence of gauge-equivalent gluon field configurations that fulfil the gauge condition, also known as Gribov copies.
A widespread belief is that the proper analysis of the low energy properties of non-abelian theories in this gauge requires, therefore, the extension of the gauge-fixing procedure, beyond the Faddeev-Popov recipe.
This manuscript reviews various applications of the Curci-Ferrari model, a phenomenological proposal for such an extension, based on the properties of Landau gauge correlators as computed on the lattice. In particular, we investigate the predictions of the model concerning the confinement/deconfinement transition of strongly interacting matter at finite temperature, first in the case of pure Yang-Mills theory for various gauge groups, and then in a formal regime of Quantum Chromodynamics where all quarks are considered heavy. We show that most qualitative aspects and also many quantitative features of the deconfinement transition in these theories can be accounted for within the Curci-Ferrari model, with only one additional parameter, adjusted from comparison to lattice simulations. Moreover, these features emerge in a systematic and controlled perturbative expansion, as opposed to the ill-defined perturbative expansion within the Faddeev-Popov model in the infrared.
The applications of the Curci-Ferrari model at finite temperature and/or density require one to consider a background extension of the Landau gauge, the so-called Landau-deWitt gauge. Therefore, besides the above mentioned applications, the manuscript is intended as a thorough but pedagogical introduction to these techniques at finite temperature and/or density, including the rationale for introducing the so-called background field effective action, the role of the Weyl chambers in discussing the various physical symmetries of the problem and the complications that emerge due to the sign problem in the case of a real quark chemical potential (in the QCD case). It also investigates the fate of the decoupling correlation functions in the presence of a background as computed in the Curci-Ferrari model and conjectures a specific behavior for the corresponding functions evaluated on the lattice, in the case of the SU(2) gauge group.
Origine | Fichiers produits par l'(les) auteur(s) |
---|