H. David Politzer

(1949 - )

Hugh David Politzer was born on August 31, 1949, in New York City. He graduated from the Bronx High School of Science in 1966, received his bachelor's degree from the University of Michigan in 1969, and his Ph.D. in 1974 from Harvard University, where his graduate advisor was Sidney Coleman.

In his first published article, which appeared in 1973, Politzer described the phenomenon of asymptotic freedom: the closer quarks are to each other, the weaker the strong interaction, given by the color charge, will be between them. When quarks are in extreme proximity, the nuclear force between them is so weak that they behave almost like free particles. This result — independently discovered at around the same time by David Gross and Frank Wilczek at Princeton University — was extremely important in the development of quantum chromodynamics, the theory of the strong nuclear interactions.

With Thomas Appelquist, Politzer also played a central role in predicting the existence of "charmonium," an elementary particle made by a charm quark and its anti-particle. Experimentalists called this the "J/? particle."

Politzer was a junior fellow at the Harvard Society of Fellows from 1974 to 1977 before moving to the California Institute of Technology, where he became a professor of theoretical physics. In 1989, he appeared in a minor role as Manhattan Project physicist Robert Serber in the movie Fat Man and Little Boy, which starred Paul Newman as General Leslie Groves.

He shared the 2004 Nobel Prize in Physics with David Gross and Frank Wilczek for their discovery of asymptotic freedom in quantum chromodynamics.

The following press release from the Royal Swedish Academy of Sciences describes the trio's work:

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