Urko Reinosa obtained his PhD in Theoretical Physics from Ecole Polytechnique (France) in 2003 after three years spent working at the Institute for Theoretical Physics of the CEA-Saclay (Commissariat à l'Energie Atomique). For the following four years he covered postdoctoral positions in various international institutions like the Institute for Theoretical Physics of the Technical University of Vienna (Austria) and the Institute for Theoretical Physics of the Ruprecht-Karl University of Heidelberg (Germany). He is currently a permanent research fellow at CNRS (Centre National de la Recherche Scientifique) in France where his research activity focuses on the properties of strongly interacting matter.

• General introduction .- Faddeev-Popov gauge fixing and the Curci-Ferrari model.- Deconfinement transition and center symmetry.- Background Field Gauges: States and Symmetries.- Background Field Gauges: Weyl chambers.- Yang-Mills deconfinement transition from the Curci-Ferrari model at leading order.- Yang-Mills deconfinement transition from the Curci-Ferrari model at next-to-leading order.- More on the relation between the center symmetry group and the deconfinement transition.- Background field gauges: adding quarks and density.- QCD decofinement transition in the heavy quark regime.- A novel look at background field methods at finite temperature.- Conclusions and outlook.- Appendix.

Urko Reinosa obtained his PhD in Theoretical Physics from Ecole Polytechnique (France) in 2003 after three years spent working at the Institute for Theoretical Physics of the CEA-Saclay (Commissariat à l'Energie Atomique). For the following four years he covered postdoctoral positions in various international institutions like the Institute for Theoretical Physics of the Technical University of Vienna (Austria) and the Institute for Theoretical Physics of the Ruprecht-Karl University of Heidelberg (Germany). He is currently a permanent research fellow at CNRS (Centre National de la Recherche Scientifique) in France where his research activity focuses on the properties of strongly interacting matter.

• General introduction .- Faddeev-Popov gauge fixing and the Curci-Ferrari model.- Deconfinement transition and center symmetry.- Background Field Gauges: States and Symmetries.- Background Field Gauges: Weyl chambers.- Yang-Mills deconfinement transition from the Curci-Ferrari model at leading order.- Yang-Mills deconfinement transition from the Curci-Ferrari model at next-to-leading order.- More on the relation between the center symmetry group and the deconfinement transition.- Background field gauges: adding quarks and density.- QCD decofinement transition in the heavy quark regime.- A novel look at background field methods at finite temperature.- Conclusions and outlook.- Appendix.

Urko Reinosa obtained his PhD in Theoretical Physics from Ecole Polytechnique (France) in 2003 after three years spent working at the Institute for Theoretical Physics of the CEA-Saclay (Commissariat à l'Energie Atomique). For the following four years he covered postdoctoral positions in various international institutions like the Institute for Theoretical Physics of the Technical University of Vienna (Austria) and the Institute for Theoretical Physics of the Ruprecht-Karl University of Heidelberg (Germany). He is currently a permanent research fellow at CNRS (Centre National de la Recherche Scientifique) in France where his research activity focuses on the properties of strongly interacting matter.

• General introduction .- Faddeev-Popov gauge fixing and the Curci-Ferrari model.- Deconfinement transition and center symmetry.- Background Field Gauges: States and Symmetries.- Background Field Gauges: Weyl chambers.- Yang-Mills deconfinement transition from the Curci-Ferrari model at leading order.- Yang-Mills deconfinement transition from the Curci-Ferrari model at next-to-leading order.- More on the relation between the center symmetry group and the deconfinement transition.- Background field gauges: adding quarks and density.- QCD decofinement transition in the heavy quark regime.- A novel look at background field methods at finite temperature.- Conclusions and outlook.- Appendix.