In 2004, the Nobel Prize in Physics was awarded to David Gross, David Politzer and Frank Wilczek for their discovery of “asymptotic freedom”. Asymptotic freedom is a startling property of quantum chromodynamics (QCD), which is the theoretical framework which physicists use to describe the fundamental forces that act deep inside protons and neutrons. I will describe in very basic terms what asymptotic freedom is and why it is so important for physics. I will also describe in very simple terms why the related (but more difficult) problem of “confinement” in QCD is central to one of the Clay Institute's Millenium Prize Problems in Mathematics: the proof of the existence of a “mass gap” in Yang-Mills theory.

Not much (if any) prior physics knowledge will be needed.