Locating the QCD Critical Point Using Holographic Black Holes

It has been shown that holographic black holes, constructed to mimic the equation of state of QCD computed on the lattice at finite temperature and zero density, display critical behavior at large baryonic chemical potential. In this proceedings, we discuss the mapping of holographic black holes into the QCD phase diagram and the emergence of the critical point and the first order phase transition line.

Dissociation of Quarkonium in Hot and Dense Media in an Anisotropic Plasma in the Nonrelativistic Quark Model

In this paper, quarkonium dissociation is investigated in an anisotropic plasma in the hot and dense media. For that purpose, the multidimensional Schrödinger equation is solved analytically by Nikiforov-Uvarov (NU) method for the real part of the potential in an anisotropic medium. The binding energy and dissociation temperature are calculated. In comparison with an isotropic medium, the binding energy of quarkonium is enhanced in the presence of an anisotropic medium. The present results show that the dissociation temperature increases with increasing anisotropic parameter for 1S state of the charmonium and bottomonium. We observe that the lower baryonic chemical potential has small effect in both isotropic and anisotropic media. A comparison is presented with other pervious theoretical works.

Status of Complex Langevin

I review the status of the Complex Langevin method, which was invented to make simulations of models with complex action feasible. I discuss the mathematical justification of the procedure, as well as its limitations and open questions. Various pragmatic measures for dealing with the existing problems are described. Finally I report on the progress in the application of the method to QCD, with the goal of determining the phase diagram of QCD as a function of temperature and baryonic chemical potential.

Bridging the two order parameters for the QCD deconfiment phase transition

We study the relation between two order parameters for deconfinement, normally employed in the literature: the continuum threshold s0, in the context of QCD Sum Rules, and the trace of the Polyakov loop ϕ in the framework of a nonlocal SU(2) chiral quark model. We establish a bridge between both order parameters at finite temperature T and baryonic chemical potential μ. In our analysis, we also include the the chiral quark condensate, the order parameter for the chiral symmetry restoration. We found that s0 and ϕ provide us with the same information for the deconfinement transition, both for the zero and finite chemical potential cases. At zero density, the critical temperatures for both quantities coincide exactly. This part of the analysis has been reinforced by the discussion of the corresponding susceptibilities and the static quark entropy behavior. At finite μ both order parameters provide evidence for the appearance of a quarkyonic phase.

Chiral logarithmic sigma model at finite temperature and baryonic chemical potential

A logarithmic potential is suggested to study the chiral phase transition, the critical temperature, and the meson masses at finite temperature and baryonic chemical potential. The logarithmic potential is based on some aspects of quantum chromodynamics (QCD) theory. The model has been solved in the mean-field approximation. We found that the behavior of meson masses takes a similar behavior as in the original sigma model and the Nambu–Jona-Lasinio model. The critical temperature is reduced in comparison with the original sigma model and it is in good agreement with recent lattice QCD results. The chiral phase transition is crossover in the case of chiral explicit breaking symmetry. The Goldstone boson theorem is studied, in which the meson mass is massive and pion mass is massless at lower temperatures. Our conclusions indicate to the present model successfully predicts the phase transition as well as in the original quark sigma model and the Nambu–Jona–Lasinio model. A new advantage of the present model, the critical temperature is in good agreement with lattice QCD results at zero chemical potential. A condition of spontaneous breaking symmetry is necessary to satisfy the Goldstone theorem in the chiral limit.

Linear Sigma Model at Finite Temperature and Baryonic Chemical Potential Using the N-Midpoint Technique

A baryonic chemical potential (μb) is included in the linear sigma model at finite temperature. The effective mesonic potential is numerically calculated using the N-midpoint rule. The meson masses are investigated as functions of the temperature (T) at fixed value of baryonic chemical potential. The pressure and energy density are investigated as functions of temperature at fi xed value of μb. The obtained results are in good agreement in comparison with other techniques. We conclude that the calculated effective potential successfully predicts the meson properties and thermodynamic properties at finite baryonic chemical potential.

Dilepton production in thermal-dependent baryonic quark–gluon plasma

We evolute a fireball of quark–gluon plasma (QGP) at thermal-dependent chemical potential (TDCP) through a statistical model in the pionic medium. The evolution of the fireball is explained through the free energy created in the pionic medium. We study the dilepton production at TDCP from such a fireball of QGP and hadronic phase. In this model, we take a finite quark mass dependence on temperature and parametrization factor. The temperature and factor enhance in the growth of the droplet formation of quarks and gluons as well as in the dilepton production rates. The production rate shows dilepton spectrum in the low mass region of the lepton pair as 0–1.2 GeV and in the intermediate mass region of 1.0–4.0 GeV. The rate of production is observed to be a strong increasing function of the TDCP for quark and antiquark annihilation. We compare the result of dilepton production at this TDCP with the production rate of the recent dilepton productions at zero and finite baryonic chemical potential and found the result far ahead in the production rates of dilepton at TDCP.

GAPLESS COLOR–FLAVOR LOCKED PHASE IN QUARK AND HYBRID STARS

We study the effects of the gapless color–flavor locked (gCFL) phase on the equation of state of strongly interacting matter in the range of baryonic chemical potential involved in a compact star. We analyze the possibility of a phase transition from hadronic matter to gCFL quark matter and we discuss, for different values of the strange quark mass and diquark coupling strength, the existence of a gCFL phase in quark or hybrid stars. The mass–radius relation and the structure of compact stars containing the gCFL phase are shown and the physical relevance of this superconducting phase inside a stellar object is also discussed.