Quark Confinement from Correlation Functions

We study quark confinement by computing the Polyakov loop potential in Yang--Mills theory within different non-perturbative functional continuum approaches [1]. We extend previous studies in the formalism of the functional renormalisation group and complement those with findings from Dyson--Schwinger equations and two-particle-irreducible functionals. These methods are formulated in terms of low order Green functions. This allows to identify a criterion for confinement solely in terms of the low-momentum behaviour of correlators.Comment: 8 pages, 3 figures. Talk given at "Xth Quark Confinement and the Hadron Spectrum", Munich, Germany, Oct. 8-12, 201

Gluon spectral functions and transport coefficients in Yang--Mills theory

We compute non-perturbative gluon spectral functions at finite temperature in quenched QCD with the maximum entropy method. We also provide a closed loop equation for the spectral function of the energy-momentum tensor in terms of the gluon spectral function. This setup is then used for computing the shear viscosity over entropy ratio $\eta/s$ in a temperature range from about $0.4\, T_c$ to $4.5\, T_c$. The ratio $\eta /s$ has a minimum at about $1.25\, T_c$ with the value of about 0.115. We also discuss extensions of the present results to QCD.Comment: 5 pages, 4 figure

From Quarks and Gluons to Hadrons: Chiral Symmetry Breaking in Dynamical QCD

We present an analysis of the dynamics of two-flavour QCD in the vacuum. Special attention is payed to the transition from the high energy quark-gluon regime to the low energy regime governed by hadron dynamics. This is done within a functional renormalisation group approach to QCD amended by dynamical hadronisation techniques. The latter allow us to describe conveniently the transition from the perturbative high-energy regime to the nonperturbative low-energy limit without suffering from a fine-tuning of model parameters. In the present work, we apply these techniques to two-flavour QCD with physical quark masses and show how the dynamics of the dominant low-energy degrees of freedom emerge from the underlying quark-gluon dynamics.Comment: 22 pages, 14 figures. v2: updated figures and discussion, matches the journal versio

Critical Point and Deconfinement from Dyson-Schwinger Equations

We employ the Dyson-Schwinger equations for quark and gluon propagators in order to study QCD with 2+1 flavours at finite temperature and density. In a suitable truncation for these equations, we determine the position of the critical end-point as well as the deconfinement temperature at all chemical potentials. For the latter, the Polyakov-loop potential is obtained from the QCD propagators. This is possible for the first time at finite chemical potential, with implications for effective models.Comment: Proceedings for the 8th International Workshop on Critical Point and Onset of Deconfinement (CPOD 2013). 5 pages, 5 figure

Polyakov loop potential at finite density

The Polyakov loop potential serves to distinguish between the confined hadronic and the deconfined quark-gluon plasma phases of QCD. For Nf=2+1 quark flavors with physical masses we determine the Polyakov loop potential at finite temperature and density and extract the location of the deconfinement transition. We find a cross-over at small values of the chemical potential running into a critical end-point at mu/T > 1.Comment: 5 pages, 9 figure

Landau gauge Yang-Mills correlation functions

We investigate Landau gauge $SU(3)$ Yang-Mills theory in a systematic vertex expansion scheme for the effective action with the functional renormalisation group. Particular focus is put on the dynamical creation of the gluon mass gap at non-perturbative momenta and the consistent treatment of quadratic divergences. The non-perturbative ghost and transverse gluon propagators as well as the momentum-dependent ghost-gluon, three-gluon and four-gluon vertices are calculated self-consistently with the classical action as only input. The apparent convergence of the expansion scheme is discussed and within the errors, our numerical results are in quantitative agreement with available lattice results.Comment: 20 pages, 13 figure

Accessibility of University Course Syllabi

Over the last twenty years, governments and a range of disability rights organizations have advocated for increased accessibility to educational materials and school documents for people with disabilities. Recently, several studies have shown that accessibility is still lagging among educational institutions and other government agencies. The purpose of this study was to analyze extant higher education syllabi to determine the level of compliance with the current Web Content Accessibility Guidelines (WCAG 2.0). The study reviewed the current accessibility requirements for schools under WCAG 2.0 and Section 508 of the Rehabilitation Act as amended in 2018. It then provides a review of 62 higher education course syllabi to determine the accessibility of each for individuals with disabilities. The study found that only 6% of syllabi fully meet accessibility criteria. Recommendations for improving accessibility are included. Keywords: Accessibility, ADA, Disabilities, Section 508, WAI, WCAG, Course material