We calculate the three-loop thermodynamic potential of QCD at finite temperature and chemical potential(s) using the hard-thermal-loop perturbation theory (HTLpt) reorganization of finite temperature and density QCD. The resulting analytic thermodynamic potential allows us to compute the pressure, energy density, and entropy density of the quark-gluon plasma. Using these we calculate the trace anomaly, speed of sound, and second-, fourth-, and sixth-order quark number susceptibilities. For all observables considered we find good agreement between our three-loop HTLpt calculations and available lattice data for temperatures above approximately 300 MeV.

We have investigated the properties of quarkonium states in an anisotropic hot QCD medium by correcting the full Cornell potential, not the Coulomb term alone as usually done in the literature, with a dielectric function from the hard-loop resummed gluon propagator. We have found that in-medium modification in anisotropic medium causes less screening than in isotropic medium. In the short distance limit, potential does not show any medium dependence whereas in the long-distance limit, it reduces to the Coulomb potential with a dynamically screened color charge. In addition, anisotropy in momentum space introduces a characteristic angular dependence in the potential and as a result, quarkonium states in anisotropic medium are more tightly bound than in isotropic medium. In particular, quark pairs aligned in the direction of anisotropy are more bound than perpendicular to the direction of anisotropy.Comment: 29 page, 6 figure

We calculate the two-loop pressure of a plasma of quarks and gluons at finite temperature and chemical potential using the hard thermal loop perturbation theory (HTLpt) reorganization of finite temperature/density quantum chromodynamics. The computation utilizes a high temperature expansion through fourth order in the ratio of the chemical potential to temperature. This allows us to reliably access the region of high temperature and small chemical potential. We compare our final result for the leading-and next-to-leading-order HTLpt pressure at finite temperature and chemical potential with perturbative quantum chromodynamics (QCD) calculations and available lattice QCD results.2

We present results of a three-loop hard-thermal-loop perturbation theory calculation of the thermodynamical potential of a finite temperature and baryon chemical potential system of quarks and gluons. We compare the resulting pressure and diagonal quark susceptibilities with available lattice data. We find reasonable agreement between our analytic results and lattice data at both zero and finite chemical potential.

Considering the general structure of the two point functions of quarks and gluons, we compute the free energy and pressure of a strongly magnetized hot and dense QCD matter created in heavy-ion collisions. In the presence of a strong magnetic field we found that the deconfined QCD matter exhibits a paramagnetic nature. One gets different pressures in directions parallel and perpendicular to the magnetic field due to the magnetization acquired by the system. We obtain both longitudinal and transverse pressures, and magnetization of hot deconfined QCD matter in the presence of the magnetic field. We have used hard thermal loop approximation for the heat bath. We obtained completely analytic expressions for pressure and magnetization under certain approximations. Various divergences appearing in free energy are regulated using appropriate counterterms. The obtained anisotropic pressure may be useful for a magnetohydrodynamics description of a hot and dense deconfined QCD matter produced in heavy-ion collisions.