Critical parameters of the liquid-gas phase transition in thermal symmetric and asymmetric nuclear matter

Abstract

The properties of critical parameters and phase diagram structure of liquid-gas phase transition are investigated in thermal symmetric and asymmetric nuclear matter with the covariant density functional (CDF) theory. Although uncertainty remains in predicting the critical parameters such as the critical temperature and pressure from various CDF functionals, several correlations are explored numerically and verified to be approximately linear between them. These correlations become worse when nuclear matter is more isospin asymmetric, resulting mainly from the effects induced by symmetry energy. By looking over the isospin dependence of the critical temperature, the role of the symmetry energy in LG transition properties of asymmetric matter is realized. The change of critical temperature with isospin asymmetry is found to be correlated well with and as a consequence could be constrained by the density slope of symmetry energy at saturation density. Then, the structure of phase diagram of thermal nuclear matter is analyzed carefully. It is revealed that the contribution from symmetry energy dominates the size of liquid-gas phase coexistence area. Moreover, the specific pattern of the phase diagram could be determined by the critical temperature at non-zero isospin asymmetry, illustrated from the correlations of the temperature with pressures at several characteristic points, paving the possible way to further explore the structure of liquid-gas phase diagram of thermal nuclear matter.

Warm dense matter and cooling of supernovae remnants

“…This adaptation of pressure is utterly important in determining the critical parameters of liquid-gas phase transition specially the critical temperature, T C . Various theoretical and experimental studies predict the value of T C for SNM in the range of 10 − 20 MeV [32,[50][51][52][53]. We also found the value of T C using Eq.…”

“…22 as 14.60, 15.37 and 14.50 MeV for NL3, G3 and IU-FSU parameter sets respectively. Other important characteristics quantities of the liquid-gas phase transition like P C , ρ C can also be determined using T C with the help of correlations derived in reference [32].…”

“…Assuming NM as an uniform system, where the fields of σ , ω and ρ mesons are independent of position and taking the thermodynamic argument of free gas into consideration, the baryon, scalar and isovector densities for the appropriate Fermi momentum at finite temperature can be evaluated as [30][31][32]…”

“…The NM system can remain only in one phase (gaseous) once it reaches the critical point [31]. For symmetric NM, the inflection point of the pressure curve with respect to the total nucleon density determines the critical point [32], that is…”

Thermodynamics of pairing transition for Odd-A nuclei

“…In particular, the study of thermodynamics is essential for compound nuclei, heavy ion collisions and induced fusions [1][2][3][4][5]. Studies have shown that the pairing correlation plays a very important role in these phenomena and other nuclear thermodynamic properties [6], such as the shape transition in hot nuclei [7,8], the phase diagram structure of liquid-gas phase transition [9,10], and the fragments produced in spallation reactions [11].…”