Large-Nc universality of phases in QCD and QCD-like theories

TL;DR

This paper discusses the large-Nc equivalences between QCD and QCD-like theories, providing a unified understanding of phases in QCD with baryon and isospin chemical potentials, relevant for heavy ion collisions.

Contribution

It introduces large-Nc equivalences that relate QCD to QCD-like theories, clarifying phase structures and the validity of phase quenching in certain regimes.

Findings

QCD with baryon chemical potential is equivalent to phase-quenched QCD in certain conditions.

Large-Nc equivalences unify understanding of phases in QCD and related theories.

Relevance to heavy ion collision experiments is established.

Abstract

QCD with a finite baryon chemical potential, despite its importance, is not well understood because the standard lattice QCD simulation is not applicable due to the sign problem. Although sign-free QCD-like theories have been studied intensively, relation to QCD with a finite baryon chemical potential was not clear until recently. In this talk we explain the large-Nc equivalences between QCD and various QCD-like theories, which lead us to a unified viewpoint for QCD with baryon and isospin chemical potentials, SO(2Nc) and Sp(2Nc) gauge theories. In particular two-flavor QCD with the baryon chemical potential is equivalent to its phase quenched version in a certain parameter region, which is relevant for heavy ion collision experiments.