An improved quasi-particle model framework for quark-gluon plasma from the path integral formalism

An improved framework for the quasi-particle model is presented. Unlike the previous approach of establishing the quasi-particle model, we introduce a classical background field (it is allowed to depend on 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 the quasi-particle system can be well defined. Based on this and following the standard ensemble theory, we construct a thermodynamically consistent quasi-particle model without the need to reformulate the statistical mechanics or the thermodynamic consistency relation. It is shown that our method is general and can be generalized to the case in which the effective mass depends not only on the temperature but also on the chemical potential. (authors)