Browsing by Author "Hussein, M. T."

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Quark-hadron phase structure, thermodynamics, and magnetization of QCD matter
(IOP PUBLISHING LTD, 2018) Tawfik, Abdel Nasser; Diab, Abdel Magied; Hussein, M. T.
The SU(3) Polyakov linear-sigma model (PLSM) is systematically implemented to characterize the quark-hadron phase structure and to determine various thermodynamic quantities and the magnetization of quantum chromodynamic (QCD) matter. Using mean-field approximation, the dependence of the chiral order parameter on a finite magnetic field is also calculated. Under a wide range of temperatures and magnetic field strengths, various thermodynamic quantities including trace anomaly, speed of sound squared, entropy density, and specific heat are presented, and some magnetic properties are described as well. Where available these results are compared to recent lattice QCD calculations. The temperature dependence of these quantities confirms our previous finding that the transition temperature is reduced with the increase in the magnetic field strength, i.e. QCD matter is characterized by an inverse magnetic catalysis. Furthermore, the temperature dependence of the magnetization showing that QCD matter has paramagnetic properties slightly below and far above the pseudo-critical temperature is confirmed as well. The excellent agreement with recent lattice calculations proves that our QCD-like approach (PLSM) seems to possess the correct degrees of freedom in both the hadronic and partonic phases and describes well the dynamics deriving confined hadrons to deconfined quark-gluon plasma.
SU(3) Polyakov linear-sigma model: Conductivity and viscous properties of QCD matter in thermal medium
(WORLD SCIENTIFIC PUBL CO, 2016) Tawfik, Abdel Nasser; Diab, Abdel Magied; Hussein, M. T.
In mean field approximation, the grand canonical potential of SU(3) Polyakov linear-sigma model (PLSM) is analyzed for chiral phase transition, sigma(l) and sigma(s) and for deconfinement order-parameters, phi and phi* of light- and strange-quarks, respectively. Various PLSM parameters are determined from the assumption of global minimization of the real part of the potential. Then, we have calculated the subtracted condensates (Delta(l), s). All these results are compared with recent lattice QCD simulations. Accordingly, essential PLSM parameters are determined. The modeling of the relaxation time is utilized in estimating the conductivity properties of the QCD matter in thermal medium, namely electric [sigma(el)(T)] and heat [kappa(T)] conductivities. We found that the PLSM results on the electric conductivity and on the specific heat agree well with the available lattice QCD calculations. Also, we have calculated bulk and shear viscosities normalized to the thermal entropy, xi/s and eta/s, respectively, and compared them with recent lattice QCD. Predictions for (xi/s)/(sigma(el)/T) and (eta/s)/(sigma(el)/T) are introduced. We conclude that our results on various transport properties show some essential ingredients, that these properties likely come up with, in studying QCD matter in thermal and dense medium.