16,843 research outputs found
QCD phase transitions via a refined truncation of Dyson-Schwinger equations
We investigate both the chiral and deconfinement phase transitions of QCD
matter in a refined scheme of Dyson-Schwinger equations, which have been shown
to be successful in giving the meson mass spectrum and matching the interaction
with the results from ab initio computation. We verify the equivalence of the
chiral susceptibility criterion with different definitions for the
susceptibility and confirm that the chiral susceptibility criterion is
efficient to fix not only the chiral phase boundary but also the critical end
point (CEP), especially when one could not have the effective thermodynamical
potential. We propose a generalized Schwinger function criterion for the
confinement. We give the phase diagram of both phase transitions and show that
in the refined scheme the position of the CEP shifts to lower chemical
potential and higher temperature. Based on our calculation and previous results
of the chemical freeze out conditions, we propose that the CEP locates in the
states of the matter generated by the Au--Au collisions with
GeV.Comment: 12 pages, 6 figures, 1 tabl
Coupling of pion condensate, chiral condensate and Polyakov loop in an extended NJL model
The Nambu Jona-Lasinio model with a Polyakov loop is extended to finite
isospin chemical potential case, which is characterized by simultaneous
coupling of pion condensate, chiral condensate and Polyakov loop. The pion
condensate, chiral condensate and the Polyakov loop as functions of temperature
and isospin chemical potential are investigated by minimizing the thermodynamic
potential of the system. The resulting phase diagram is studied
with emphasis on the critical point and Polyakov loop dynamics. The tricritical
point for the pion superfluidity phase transition is confirmed and the phase
transition for isospin symmetry restoration in high isospin chemical potential
region perfectly coincides with the crossover phase transition for Polyakov
loop. These results are in agreement with the Lattice QCD data.Comment: 15pages, 8 figure
Interface Effect in QCD Phase Transitions via Dyson-Schwinger Equation Approach
With the chiral susceptibility criterion we obtain the phase diagram of
strong-interaction matter in terms of temperature and chemical potential in the
framework of Dyson-Schwinger equations (DSEs) of QCD.After calculating the
pressure and some other thermodynamic properties of the matter in the DSE
method, we get the phase diagram in terms of temperature and baryon number
density. We also obtain the interface tension and the interface entropy density
to describe the inhomogeneity of the two phases in the coexistence region of
the first order phase transition. After including the interface effect, we find
that the total entropy density of the system increases in both the
deconfinement (dynamical chiral symmetry restoration) and the hadronization
(dynamical chiral symmetry breaking) processes of the first order phase
transitions and thus solve the entropy puzzle in the hadronization process.Comment: 9 pages, 9 figures, and 1 tabl
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