Heavy ion collisions and black hole dynamics

Relativistic heavy ion collisions create a strongly coupled quarkgluon plasma. Some of the plasma's properties can be approximately understood in terms of a dual black hole. These properties include shear viscosity, thermalization time, and drag force on heavy quarks. They are hard to calculate from first principles in QCD. Extracting predictions about quarkgluon plasmas from dual black holes mostly involves solving Einstein's equations and classical string equations of motion. AdS/CFT provides a translation from gravitational calculations to gauge theory predictions. The gauge theory to which the predictions apply is $\mathcal{N} = 4$ super-YangMills theory. QCD is different in many respects from super-YangMills, but it seems that its high temperature properties are similar enough for us to make some meaningful comparisons.