出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Applying Monte-Carlo methods to the Polyakov-loop extended Nambu–Jona-Lasinio (PNJL) model we go beyond the saddle-point approximation in a mean-field calculation and introduce fluctuations around the mean fields. The impact of fluctuations on the thermodynamics of the model in the two-flavor case becomes evident by studying the second-order Taylor expansion coefficients of the thermodynamic grand-canonical partition function with respect to the quark chemical potential. Here we show a comparison with extrapolations from lattice QCD. We find that in order to reproduce lattice data for the flavor non-diagonal quark susceptibilities the introduction of fluctuations is unavoidable.
