Sphaleron rate in hot QCD

I explain why real-time topology change is important in Quantum Chromodynamics (QCD). Above Tc this is controlled by so-called sphaleron transitions. After explaining the difference between instantons and sphalerons, I present a new technique for determining the real-time sphaleron rate in QCD using only Euclidean lattice gauge theory techniques. The technique is fully nonperturbative, and results within quenched QCD are already available, with the extension to full QCD underway.