Density Fluctuations as Signature of a Non--Equilibrium First Order Phase Transition

TL;DR

This paper demonstrates that density fluctuations during a non-equilibrium first order phase transition can be as significant as at the critical end point, providing a new way to probe phase transitions in heavy ion collisions.

Contribution

It reveals that spinodal instabilities cause strong charge fluctuations during a first order transition, comparable to those at the critical end point.

Findings

Net baryon number susceptibility diverges at spinodal lines.

Charge density fluctuations are enhanced during non-equilibrium first order transitions.

Fluctuations can serve as signatures for both CEP and first order phase transitions.

Abstract

We show that in the presence of spinodal instabilities which develop at a first order phase transition, the fluctuations of conserved charges can be as strong as those at the critical end point (CEP). In particular, the net baryon number susceptibility diverges as the system crosses the isothermal spinodal lines. This indicates that charge density fluctuations can be used not only to probe the CEP but also the non--equilibrium first order chiral phase transition in heavy ion collisions.