Thermodynamics of 5D dilaton-gravity

We calculate the free energy, spatial string tension and Polyakov loop of the gluon plasma using the dilaton potential of Ref. arXiv:0911.0627[hep-ph] in the dilaton-gravity theory of AdS/QCD. The free energy is computed from the Black Hole solutions of the Einstein equations in two ways: first, from the Bekenstein-Hawking proportionality of the entropy with the area of the horizon, and secondly from the Page-Hawking computation of the free energy. The finite temperature behaviour of the spatial string tension and Polyakov loop follow from the corresponding string theory in AdS_5. Comparison with lattice data is made.Comment: 3 pages, 3 figures. Talk given at the IX International Conference on Quark Confinement and the Hadron Spectrum (QCHS9), Madrid, Spain, 30 Aug. - 3 Sep. 201

One-loop effective action of QCD at high temperature using the heat kernel method

Perturbation theory is an important tool to describe the properties of QCD at very high temperatures. Recently a new technique has been proposed to compute the one-loop effective action of QCD at finite temperature by making a gauge covariant derivative expansion, which is fully consistent with topologically small and large gauge transformations (also time dependent transformations). This technique is based on the heat kernel expansion, and the thermal Wilson line plays an essential role. We consider a general SU(N_c) gauge group.Comment: 3 pages, no figures. Proceedings for IX Hadron Physics and VII Relativistic Aspects of Nuclear Physics, Angra dos Reis, Rio de Janeiro, March 28 - April 03, 200

Correlation between conserved charges in PNJL Model with multi-quark interactions

We present a study of correlations among conserved charges like baryon number, electric charge and strangeness in the framework of 2+1 flavor Polyakov loop extended Nambu-Jona-Lasinio model at vanishing chemical potentials, up to fourth order. Correlations up to second order have been measured in Lattice QCD which compares well with our estimates given the inherent difference in the pion masses in the two systems. Possible physical implications of these correlations and their importance in understanding the matter obtained in heavy-ion collisions are discussed. We also present comparison of the results with the commonly used unbound effective potential in the quark sector of this model

Susceptibilities with multi-quark interactions in PNJL model

We have investigated the fluctuations and the higher order susceptibilities of quark number, isospin number, electric charge and strangeness at vanishing chemical potential for 2+1 flavor Polyakov loop extended Nambu--Jona-Lasinio model. The calculations are performed for the bound effective potential in the quark sector requiring up to eight quark interaction terms. These have been contrasted to the lattice results which currently have somewhat heavier quarks in the light flavor sector. The results show sufficient qualitative agreement. For comparison we also present the results obtained with the conventional effective potential containing upto six quark interaction terms.Comment: To appear Physical Review

Chiral Lagrangians at finite temperature and the Polyakov Loop

Heat kernel expansions at finite temperature of massless QCD and chiral quark models generate effective actions relevant for both low and high temperature QCD. The key relevance of the Polyakov Loop to maintain the large and non-perturbative gauge invariance at finite temperature is stressed.Comment: Talk given at 6th Conference on Quark Confinement and the Hadron Spectrum, Villasimius, Sardinia, Italy, 21-25 Sep 200