Chiral soliton model at finite temperature and density

Abstract

In mean field approximation, we study a chiral soliton of the linear sigma model with two flavors at finite temperature and density. The stable soliton solutions are calculated with some appropriate boundary conditions. Energy and radius of the soliton are determined in a hot medium of constituent quarks. It is found that for $T<T_c$, the energy of the soliton $E^*$ is less than the energy of three constituent quarks $3M_q$, but with the increasing of temperature, the difference between $E^*$ and $3M_q$ becomes smaller and smaller, once $T>T_c$, there is a sharp delocalization phase transition from hadron matter to quark matter coincident with the restoration of chiral symmetry. In the transition region, the thermodynamic properties show large discontinuities which is an indication for a first-order phase transition.Comment: 14 pages, 7 figures, version accepted for publication in Physical Review

Nucleon properties in the quantized linear sigma model at finite temperature and chemical potential

“…In addition, one avoids assumptions like the hedgehog structure of the quark and pion fields that are taken in many works at finite temperature and density such as in Ref. [17] and the references therein. So far no attempt has been made to include the finite chemical potential by using the coherent-pair approximation.…”

Nucleon properties in the Polyakov quark-meson model

“…It has been proved in Refs. [17,26] that this parameter set can successfully describe the properties of nucleon in vacuum.…”

“…Under the above treatment, the PQM model now is simplified as the classical chiral soliton model and the well-known results already exhibited in the chiral soliton model in Ref. [17] can be duplicated with the exception that the nucleons do not penetrate into the solitons unless the nucleons start to overlap with each other when the temperature is near the critical temperature for the QCD deconfinement phase transition. fields in the chiral-symmetry-breaking phase.…”

Nontopological soliton in the Polyakov quark-meson model

“…However, the stability of such baryonic phase should be checked carefully by comparing the total energy of the system in thermal medium with the energy of three free constituent quarks in the system. By subtracting the homogeneous medium contribution [34] [51], the total energy of system M N is plotted as a function of the temperature for µ = 0MeV and µ = 380MeV in Fig.6. Here, one finds that for a smooth crossover of the symmetry breaking patten at low density region, both M N and 3M q fall smoothly from the corresponding vacuum value as T goes to high temperature.…”