A thermodynamically consistent quasi-particle model without temperature-dependent infinity of the vacuum zero point energy

作者：Cao, Jing; Jiang, Yu; Sun, Wei-min; Zong, Hong-shi^*

来源：Physics Letters B, 2012, 711(1): 65-70.

DOI：10.1016/j.physletb.2012.03.079

• EQUATION-OF-STATE
• QUARK-GLUON PLASMA
• 3-LOOP FREE-ENERGY
• QCD PHASE-DIAGRAM
• TRANSITION
• DENSITIES

In this Letter, an improved quasi-particle model is presented. Unlike the previous approach of establishing quasi-particle model, we introduce a classical background field (it is allowed to depend on the temperature) to deal with the infinity of thermal vacuum energy which exists in previous quasi-particle models. After taking into account the effect of this classical background field, the partition function of quasi-particle system can be made well-defined. Based on this and following the standard ensemble theory, we construct a thermodynamically consistent quasi-particle model without the need of any reformulation of statistical mechanics or thermodynamical consistency relation. As an application of our model, we employ it to the case of (2 + 1) flavor QGP at zero chemical potential and finite temperature and obtain a good fit to the recent lattice simulation results of Borsanyi et al. A comparison of the result of our model with early calculations using other models is also presented. It is shown that our method is general and can be generalized to the case where the effective mass depends not only on the temperature but also on the chemical potential.

• 出版日期2012-5-1
• 单位浙江师范大学; 南京大学