Strongly Interacting Matter at High Energy Density

TL;DR

This paper reviews the properties of strongly interacting matter described by QCD at high energy densities, including phase transitions, Quarkyonic Matter, and the Color Glass Condensate, highlighting recent theoretical developments.

Contribution

It introduces the concept of Quarkyonic Matter and discusses the role of the Color Glass Condensate in high energy QCD phenomena.

Findings

High temperature matter undergoes deconfinement transition.

Quarkyonic Matter is a distinct phase at high baryon density and low temperature.

Color Glass Condensate governs the low x structure of hadrons.

Abstract

This lecture concerns the properties of strongly interacting matter (which is described by Quantum Chromodynamics) at very high energy density. I review the properties of matter at high temperature, discussing the deconfinement phase transition . At high baryon density and low temperature, large $N_c$ arguments are developed which suggest that high baryonic density matter is a third form of matter, Quarkyonic Matter, that is distinct from confined hadronic matter and deconfined matter. I finally discuss the Color Glass Condensate which controls the high energy limit of QCD, and forms the low x part of a hadron wavefunction. The Glasma is introduced as matter formed by the Color Glass Condensate which eventually thermalizes into a Quark Gluon Plasma.