Density fluctuations and chiral phase transition

TL;DR

This paper investigates charge density fluctuations near the chiral phase transition in QCD, highlighting divergence during spinodal decomposition in non-equilibrium first order transitions, and discusses associated critical exponents.

Contribution

It demonstrates that charge density fluctuations diverge not only at the critical end point but also along the first order phase transition with spinodal separation, using mean field dynamics.

Findings

Charge fluctuations diverge during spinodal decomposition.

Divergent fluctuations occur along first order transition, not only at critical point.

Critical exponents for charge susceptibilities are discussed.

Abstract

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.