Transport and spectral functions in high-temperature QCD

TL;DR

This paper reviews the current understanding of transport coefficients and spectral functions in high-temperature QCD, comparing weak and strong coupling approaches and recent lattice QCD developments.

Contribution

It provides a comprehensive comparison of weak and strong coupling methods for calculating transport properties in high-temperature QCD and discusses recent lattice QCD advancements.

Findings

Weak coupling results via kinetic theory and diagrammatic techniques.

Strong coupling results from gauge/gravity duality.

Recent lattice QCD extractions of spectral functions.

Abstract

The current status of transport coefficients in relativistic field theories at high temperature is reviewed. I contrast weak coupling results obtained using kinetic theory/diagrammatic techniques with strong coupling results obtained using gauge/gravity duality, and describe the recent developments in extracting transport coefficients and spectral functions from lattice QCD simulations. The fate of quarkonium at high temperature as seen from the lattice is briefly mentioned as well.