Related papers: Gluon Condensation in Nonperturbative Flow Equatio…
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…
Models based on Yang-Mills condensate (YMC) have been advocated in the literature and claimed to be successful candidates to explain dark energy. Several instantiations of this simple idea have been considered, the most promising of which…
We study Landau-gauge Yang-Mills theory by means of a nonperturbative vertex expansion of the quantum effective action. Using an exact renormalization group equation, we compute the fully dressed gluon and ghost propagators to lowest…
Composite operators of bare fermion fields evolved along a trajectory on field space by means of flow equations are multiplicatively renormalized. Therefore, even in the case of Wilson fermions, the renormalization of expectation values of…
We discuss the concept of gauge-invariant fields for non-abelian gauge theories. Infinitesimal fluctuations around a given gauge field can be split into physical and gauge fluctuations. Starting from some reference field the gauge-invariant…
The lowest dimensional gluon condensate $G_2$ is analysed at finite temperature and chemical potential using a bottom/up holographic model of QCD. Starting from the free energy of the model, pressure, entropy and quark density are obtained.…
An effective low energy action for Yang-Mills theories is proposed, which invokes an additional auxiliary field $H_{\mu \nu}$ for the field strength $F_{\mu \nu}$. For a particular relation between the parameters of this action a gluon…
A new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge is presented and solved for the static gluon and ghost propagators under the assumption of ghost dominance. The results are compared to those…
We present an exact nonperturbative flow equation for the average action for quarks which incorporates the effects of gluon fluctuations. With suitable truncations this allows one to compute effective multiquark interactions in dependence…
Confinement in non-Abelian gauge theories is commonly ascribed to percolation of magnetic monopoles, or strings in the vacuum. At the deconfinement phase transition the condensed magnetic degrees of freedom are released into gluon plasma as…
We give an argument for deriving analytically the infrared ``Abelian'' dominance in a gauge invariant way for the Wilson loop average in SU(2) Yang--Mills theory. In other words, we propose a possible mechanism for realizing the dynamical…
A new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge is presented and solved for the static gluon and ghost propagators under the assumption of ghost dominance. The results are compared to those…
I consider the chromomagnetic vacuum in SU(2). The effective Lagrangian in one loop approximation is known to have a minimum below zero which results in a spontaneously generated magnetic field. However, this minimum is not stable; the…
We have formulated new quantum model of the QCD vacuum using the effective potential approach for composite operators. It is based on the existence and importance of such kind of the nonperturbative, topologically nontrivial excitations of…
The Yang--Mills gradient flow and its extension to the fermion field provide a very general method to obtain renormalized observables in gauge theory. The method is applicable also with non-perturbative regularization such as lattice. The…
In this thesis we investigate two different sets of physics questions, aiming at a better understanding of the low-energy behaviour of Yang-Mills theories, and the properties connected to confinement, in a first part. In a second part, we…
Phenomenological evidence and analytic approximations to the QCD ground state suggest a complex gluon condensate structure. Exclusion of elementary fermion excitations by the generation of infinite mass corrections is a consequence. In…
We derive the Polyakov-loop thermodynamic potential in the perturbative approach to pure SU(3) Yang-Mills theory. The potential expressed in terms of the Polyakov loop in the fundamental representation corresponds to that of the…
The dual superconductivity is believed to be a promising mechanism for quark confinement. Indeed, what this picture is true has been confirmed in the maximal Abelian (MA) gauge. However, it is not yet confirmed in any other gauge and the MA…
The quark <\bar\psi \psi> and gluon <F_{\mu\nu}F^{\mu\nu}> vacuum expectation values are non-vanishing at low orders in \alpha_s when the perturbative ground state includes quark and gluon pairs. This offers possibilities of studying the…