Density fluctuations and chiral phase transition

Based on an effective QCD Lagrangian we discuss the properties of charge density fluctuations in the vicinity of chiral phase transition. We explore thermodynamics in the presence of spinodal phase separation. We show that appearance of spinodal decomposition in a non-equilibrium first order phase transition results in divergence of the charge density fluctuations related with the electric charge and baryon number conservation. Consequently, divergent fluctuations at the chiral phase transition are not only attributed to the critical end point but are also there along the first order phase transition if the spinodal phase separation take place. Based on the mean field dynamics, the critical exponents for these singular behavior of charge susceptibilities are also discussed.