Three regimes/phases of QCD at high T, their symmetries and N_c scaling

TL;DR

This paper reviews recent progress in understanding the QCD phase diagram at small chemical potentials, identifying three distinct regimes characterized by different symmetries, degrees of freedom, and N_c scaling.

Contribution

It categorizes the QCD phases at high temperature into three regimes, detailing their symmetries and N_c scaling, and summarizes recent developments.

Findings

Identifies three distinct QCD regimes with different symmetries.

Describes the degrees of freedom in each phase.

Analyzes N_c scaling across phases.

Abstract

We review recent developments on the QCD phase diagram at small chemical potentials and increasing temperature. There are three regimes/phases in QCD which differ by symmetries, degrees of freedom and N_c scaling: the hadron gas below the chiral restoration temperature T_ch, the stringy fluid between T_ch and the deconfinement temperature T_d and the quark-gluon plasma above T_d.