2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/176585We discuss results from lattice calculations for a few observables that are sensitive to different length scales in the high temperature phase of QCD and can give insight into its non-perturbative structure. We compare lattice results with perturbative calculations at high temperature obtained for vanishing and non-vanishing quark chemical potential.plenary talk given at Hard Probes 2006, June 9-16, 2006, Asilomar, CA, USA; 9 pages, 10 EPS-figuresHigh Energy Physics - Phenomenologytext