David Gross

(1941 - )

David Jonathan Gross was born on February 19, 1941, in Washington, D.C. Gross received his bachelor's degree and master's degree from the Hebrew University of Jerusalem, Israel, in 1962. He received his Ph.D. in physics from the University of California, Berkeley in 1966 and was a Junior Fellow at Harvard University and a Professor at Princeton University until 1997. He is the recipient of a MacArthur Foundation Fellowship in 1987, the Dirac Medal in 1988, and currently is the director and holder of the Frederick W. Gluck Chair in Theoretical Physics at the Kavli Institute for Theoretical Physics of the University of California, Santa Barbara.

Along with Frank Wilczek and David Politzer, he was awarded the 2004 Nobel Prize in Physics for his discovery of asymptotic freedom. In 1973, Gross, working with his first graduate student, Frank Wilczek, at Princeton University, discovered asymptotic freedom, which holds that the closer quarks are to each other, the less the strong interaction (or color charge) between them; when quarks are in extreme proximity, the nuclear force between them is so weak that they behave almost as free particles. Asymptotic freedom, independently discovered by David Politzer, was important for the development of quantum chromodynamics. Gross, with Jeff Harvey, Emil Martinec, and Ryan Rohm also discovered heterotic string.

The following press release from the Royal Swedish Academy of Sciences describes the work of Wilczek, Politzer, and Gross:

What are the smallest building blocks in Nature? How do these particles build up everything we see around us? What forces act in Nature and how do they actually function?

This year's Nobel Prize in Physics deals with these fundamental questions, problems that occupied physicists throughout the 20th century and still challenge both theoreticians and experimentalists working at the major particle accelerators.

David Gross, David Politzer and Frank Wilczek have made an important theoretical discovery concerning the strong force, or the 'colour force' as it is also called. The strong force is the one that is dominant in the atomic nucleus, acting between the quarks inside the proton and the neutron. What this year's Laureates discovered was something that, at first sight, seemed completely contradictory. The interpretation of their mathematical result was that the closer the quarks are to each other, the weaker is the 'colour charge'. When the quarks are really close to each other, the force is so weak that they behave almost as free particles. This phenomenon is called ”asymptotic freedom”. The converse is true when the quarks move apart: the force becomes stronger when the distance increases. This property may be compared to a rubber band. The more the band is stretched, the stronger the force.

This discovery was expressed in 1973 in an elegant mathematical framework that led to a completely new theory, Quantum ChromoDynamics, QCD. This theory was an important contribution to the Standard Model, the theory that describes all physics connected with the electromagnetic force (which acts between charged particles), the weak force (which is important for the sun's energy production) and the strong force (which acts between quarks). With the aid of QCD physicists can at last explain why quarks only behave as free particles at extremely high energies. In the proton and the neutron they always occur in triplets.

Thanks to their discovery, David Gross, David Politzer and Frank Wilczek have brought physics one step closer to fulfilling a grand dream, to formulate a unified theory comprising gravity as well – a theory for everything.

Sources: Wikipedia, Nobelprize.org