David Jonathan Gross
active c. 1941, Washington, D.C., United States
American theoretical physicist, co-discoverer of the asymptotic freedom of the strong interaction — foundation of quantum chromodynamics; later director of KITP.
Gross earned his PhD at Berkeley in 1966 then joined Princeton, becoming professor in 1972. With his student Frank Wilczek he computed the beta function of Yang–Mills theory and found its famous negative sign in 1973.
Asymptotic freedom — the strong force weakening at short distance — explained deep inelastic scattering and led to quantum chromodynamics (QCD). He was also co-author of the 'heterotic string' (an ancestor of string theory I). In 1997 he moved to UC Santa Barbara as director of the Kavli Institute for Theoretical Physics. He shared the 2004 Nobel Prize.
Nobel-winning work
Deep inelastic electron–proton scattering at SLAC (1969) showed quarks behaving almost free inside the nucleon — contradicting the enormous strength of their interaction. In 1973 Gross and Wilczek (and independently Politzer) computed the running coupling of non-Abelian Yang–Mills theory: the β function is negative, meaning the effective coupling decreases as energy grows — 'asymptotic freedom'.
The result explained both nearly-free quarks at high energy and confinement at low energy. Together with Gell-Mann's color idea it became QCD — the precise theory of the strong interaction, predicting hadron spectra and structure-function evolution to this day. The three shared the 2004 Nobel 'for the discovery of asymptotic freedom in the theory of the strong interaction'.
Workplaces: University of California, Santa Barbara (KITP), Princeton University
United States