Happy birthday David Politzer! Born in 1949 in New York City, Politzer earned a PhD in physics at Harvard in 1974 -- one year after he had published the paper that would later earn him a share of the 2004 Nobel physics prize. In that paper Politzer described "asymptotic freedom": the closer quarks are to each other, the weaker the strong interaction will be between them -- to the point that the force all but vanishes when the quarks are in extreme proximity. Derived independently by David Gross and Frank Wilczek, asymptotic freedom is a key ingredient of quantum chromodynamics. Among Politzer's current interests is the physical origin of the banjo's characteristic sound, which remains challenging to calculate because the banjo's bridge rests on a vibrating membrane.
