Professor emeritus, alumnus win Nobel Prize

An emeritus University professor and his former graduate student have been awarded the 2004 Nobel Prize in Physics for a theory they refined while working together in the 1970s, the Royal Swedish Academy of Sciences announced Tuesday.

David Gross and Frank Wilczek GS '75, along with David Politzer, received the award for their work involving the forces that hold atoms together. Although Gross and Wilczek are now working at the University of California-Santa Barbara and the Massachusetts Institute of Technology, respectively, they are still well remembered by their colleagues at the University's physics department.

Neither Gross nor Wilczek could be reached for comment Tuesday night.

Gross and Wilczek, as a young faculty member and graduate student, respectively, formulated their revolutionary theory in the early 1970s while holed up in the third floor of Jadwin Hall, according to members of the department.

They worked out their theory with pencil and paper, applying mathematical reasoning to microcosmic quirks observed in nature.

Gross and Wilczek's discovery concerned a subatomic interaction called the "strong force."

The strong force is one of the four basic forces in nature that act on matter and control its movement.

While the first force — gravity — is easily observed, the others are detectable only on the microcosmic level: electromagnetic interaction, weak interaction and strong interaction.

These forces dictate the interactions between atoms and their constituent parts, and together make up the mathematical Standard Model that is the base of quantum mechanics.

Until the 1960s, scientists thought atoms were only made up of protons and neutrons, with electromagnetic interaction controlling the movement between them.

Then they discovered protons and neutrons are made up of still smaller elements called quarks.

But although they could detect quarks, scientists couldn't isolate them or explain their interactions. What were the forces holding these tiny composites together?

Get the best of the ‘Prince’ delivered straight to your inbox. Subscribe now »

The answer, Gross and Wilczek discovered, was a special property now called the "color charge."

Each of the three quarks in a proton carries a different color charge, which is emitted in a way similar to the positive or negative electric charge of protons and electrons.

These color forces between quarks cause them to bind together, forming a "white" charge, in the same way charged atoms bind to make neutrally charged molecules.

"It's a quite subtle theory, and [Gross and Wilczek] understood it at a fundamental level no one else did," physics department chair Dan Marlowe said.

"It wasn't just a description — it was a theory based on really rigorous mathematics," he said.

The young professor and his student published their theory in a 1973 edition of the scientific journal Physical Review Letters. Fellow winner Politzer published a subsequent article in the journal describing strong forces in more detail.

Expressing pride at Gross and Wilczek's accomplishment, Marlowe said, "Princeton has a great faculty, especially in the sciences. We already have several Nobel Laureates on staff [in the physics department]."

Professor emeritus Philip Anderson is one such honoree, winning the award in 1977. Anderson congratulated Gross and Wilczek, adding that winning the Nobel Prize is a singular and moving experience.

"It was the only time in my life I've gotten a real ovation and that's really amazing if you aren't used to it," Anderson said. "Unless you're a rock star or something."