From Heavy-Ion Collisions to Compact Stars: Equation of State and Relevance of the System Size

In this article, we start by presenting state-of-the-art methods allowing us to compute moments related to the globally conserved baryon number, by means of first principle resummed perturbative frameworks. We focus on such quantities for they convey important properties of the finite temperature and density equation of state, being particularly sensitive to changes in the degrees of freedom across the quark-hadron phase transition. We thus present various number susceptibilities along with the corresponding results as obtained by lattice quantum chromodynamics collaborations, and comment on their comparison. Next, omitting the importance of coupling corrections and considering a zero-density toy model for the sake of argument, we focus on corrections due to the small size of heavy-ion collision systems, by means of spatial compactifications. Briefly motivating the relevance of finite size effects in heavy-ion physics, in opposition to the compact star physics, we present a few preliminary thermodynamic results together with the speed of sound for certain finite size relativistic quantum systems at very high temperature.Comment: 10 pages, 9 figures. Published version -- MDPI journal Univers

The 2030 global education agenda and teachers, teaching and teacher education

The Millennium Development Goals (MDGs) and Education for all (EFA) Goals have been replaced by a Sustainable Development Framework with a new set of arguably more ambitious goals and targets. The most recent report Transforming Our World: The 2030 Agenda For Sustainable Development highlights this framework and outlines the education goals. The overarching goal that has been put forward for education is to Ensure Inclusive and Equitable Quality Education and Promote Lifelong Learning Opportunities for All. The targets associated with this goal between them cover all educational levels from early childhood development and care to scholarships for Higher Education and crucially teachers and teacher supply. In this context, we discuss the continuities and discontinues in the new SDG quality agenda through an analysis of the policy debates and documents about the evolving framework paying particular attention to how quality is conceptualised ,how it is translated into targets and how teachers are located in the global education quality discourse and governance frameworks. The analysis will be rooted in a discussion of what this changed global education agenda means for teacher education, teaching, and teachers. The paper argues for the notion of education quality as a dynamic, process oriented social justice process. Yusuf Sayed is the Professor of International Education and Development Policy at the University of Sussex He is also a Senior Research Fellow at the Institute of Social and Economic Research (ISER), Rhodes University, South Africa. . He was also the South African Research Chair in Teacher Education, and the Founding Director of the Centre for International Teacher Education (CITE), 2014-2017 at the Cape Peninsula University of Technology (CPUT), South Africa. Peviously Yusuf was Senior Policy Analyst at the EFA Global Monitoring Report, UNESCO, Team Leader for Education and Skills, the Department for International Development UK, and Head of Department of Comparative Education at the University of the Western Cape, South Africa. Yusuf is an education policy specialist with a career in international education and development research. He is presently engaged in several research projects on teachers and teacher education including the ESRC/DFID funded project “Engaging teachers in peacebuilding in post conflict contexts: evaluating education interventions in Rwanda and South Africa and several large-scale studies about teacher professionalism, teacher education and continuing professional development in South Africa and globally

Non-extensivity of the QCD pT spectra

We try to establish a connection between the hadronic distributions, in proton-proton collisions at very high transverse momentum $p_{\mathrm{T}}$, obtained via perturbative QCD and the Tsallis non extensive statistics. Our motivation is that while the former is expected to be valid at extremely high momentum, due to asymptotic freedom, the latter has been very successful in describing experimental spectra over a wide range of momentum. Matching the non extensive statistics with the asymptotic $p_{\mathrm{T}}$ behaviour expected from QCD leads to the value of $q=1.25$.Comment: 4 page

Three loop HTL perturbation theory at finite temperature and chemical potential

In this proceedings contribution we present a recent three-loop hard-thermal-loop perturbation theory (HTLpt) calculation of the thermodynamic potential for a finite temperature and chemical potential system of quarks and gluons. We compare the resulting pressure, trace anomaly, and diagonal/off-diagonal quark susceptibilities with lattice data. We show that there is good agreement between the three-loop HTLpt analytic result and available lattice data.Comment: 4 pages, 4 figure

Analytic results for the Tsallis thermodynamic variables

We analytically investigate the thermodynamic variables of a hot and dense system, in the framework of the Tsallis non-extensive classical statistics. After a brief review, we start by recalling the corresponding massless limits for all the thermodynamic variables. We then present the detail of calculation for the exact massive result regarding the pressure -- valid for all values of the $q$-parameter -- as well as the Tsallis $T$-, $mu$- and $m$- parameters, the former characterizing the non-extensivity of the system. The results for other thermodynamic variables, in the massive case, readily follow from appropriate differentiations of the pressure, for which we provide the necessary formulas. For the convenience of the reader, we tabulate all of our results. A special emphasis is put on the method used in order to perform these computations, which happens to reduce cumbersome momentum integrals into simpler ones. Numerical consistency between our analytic results and the corresponding usual numerical integrals are found to be perfectly consistent. Finally, it should be noted that our findings substantially simplify calculations within the Tsallis framework. The latter being extensively used in various different fields of science as for example, but not limited to, high-energy nucleus collisions, we hope to enlighten a number of possible applications. Bhattacharyya, Trambak; Cleymans, Jean; Mogliacci, Sylvai

Teachers' capability-related subjective theories in teaching and learning relations

Jancic Mogliacci R. Teachers' capability-related subjective theories in teaching and learning relations. Bielefeld: Universitätsbibliothek Bielefeld; 2015

Probing the finite density equation of state of QCD via resummed perturbation theory

Mogliacci S. Probing the finite density equation of state of QCD via resummed perturbation theory. Bielefeld: University of Bielefeld; 2014.In this Ph.D. thesis, the primary goal is to present a recent investigation of the finite density thermodynamics of hot and dense quark-gluon plasma. As we are interested in a temperature regime, in which naive perturbation theory is known to lose its predictive power, we clearly need to use a refined approach. To this end, we adopt a resummed perturbation theory point of view and employ two different frameworks. We first use hard-thermal-loop perturbation theory (HLTpt) at leading order to obtain the pressure for nonvanishing quark chemical potentials, and next, inspired by dimensional reduction, resum the known four-loop weak coupling expansion for the quantity. We present and analyze our findings for various cumulants of conserved charges. This provides us with information, through correlations and fluctuations, on the degrees of freedom effectively present in the quark-gluon plasma right above the deconfinement transition. Moreover, we compare our results with state-of-the-art lattice Monte Carlo simulations as well as with a recent three-loop mass truncated HTLpt calculation. We obtain very good agreement between the two different perturbative schemes, as well as between them and lattice data, down to surprisingly low temperatures right above the phase transition. We also quantitatively test the convergence of an approximation, which is used in higher order loop calculations in HTLpt. This method based on expansions in mass parameters, is unavoidable beyond leading order, thus motivating our investigation. We find the ensuing convergence to be very fast, validating its use in higher order computations