# Phase transitions in quantum chromodynamics

## TL;DR

This paper reviews the current understanding of finite temperature phase transitions in QCD, discussing theoretical predictions, experimental implications, and the importance of nonequilibrium effects in heavy-ion collisions.

## Contribution

It provides a comprehensive review of phase transition criteria, analytical tools beyond mean-field models, and explores nonequilibrium approaches in QCD thermodynamics.

## Key findings

- Comparison of theoretical predictions with experimental data
- Identification of areas needing more reliable QCD equation of state data
- Discussion of nonequilibrium effects in heavy-ion collision thermodynamics

## Abstract

The current understanding of finite temperature phase transitions in QCD is reviewed. A critical discussion of refined phase transition criteria in numerical lattice simulations and of analytical tools going beyond the mean-field level in effective continuum models for QCD is presented. Theoretical predictions about the order of the transitions are compared with possible experimental manifestations in heavy-ion collisions. Various places in phenomenological descriptions are pointed out, where more reliable data for QCD's equation of state would help in selecting the most realistic scenario among those proposed. Unanswered questions are raised about the relevance of calculations which assume thermodynamic equilibrium. Promising new approaches to implement nonequilibrium aspects in the thermodynamics of heavy-ion collisions are described.