Nobel laureate 't Hooft to discuss breakthrough that revolutionized physics

By Eric McHenry

In the early 1960s, Sheldon Lee Glashow -- who was recently named the first Arthur G. B. Metcalf Professor of Science at BU -- began laying the foundation for what has become the standard model of particle physics. But little was done with his theory for nearly a decade, as physicists puzzled over how to calculate with and test it.

Gerard 't Hooft

Then a precocious graduate student named Gerard 't Hooft came up with the necessary mathematical tools. On April 25, 't Hooft will visit the Metcalf Science Center as the 19th Dean S. Edmonds, Sr. Memorial Lecturer.

Building on earlier advances made by Martinus J. G. Veltman, his graduate thesis advisor at Utrecht University in the Netherlands, 't Hooft showed how to calculate using the unified theory of electromagnetic and weak interactions. This "electroweak" theory, introduced and developed in the 1960s by Glashow, Steven Weinberg, and Abdus Salam, underlies all of particle physics and provides a framework for understanding how the early universe evolved. All five scientists were subsequently honored with the Nobel prize -- Glashow, Weinberg, and Salam in 1979, 't Hooft and Veltman last year.

"For a decade, people didn't know how to calculate beyond the most elementary level with this model," says Kenneth Lane, CAS professor of physics. "It was impossible. And so the model was more or less forgotten.

"Then Gerard and his thesis advisor, Tini Veltman, showed how to do it. Their findings came out in 1971, and it was a bombshell. Everybody immediately jumped onto this theory, and over the decade it became clear that Glashow, Weinberg, and Salam's model was correct. Experiments verified it in every detail."

In an address entitled A Confrontation with Infinity, 't Hooft will speak about the field of particle physics before and after his discovery. Although it took the Royal Swedish Academy of Sciences nearly 30 years to reward 't Hooft and Veltman for their breakthrough, its impact was immediately felt among physicists, Lane says.

"The importance of their work was unquestioned from the moment it appeared," he says. "I remember; I was a young post-doc. And I immediately stopped what I was doing and started working on it. So did everyone else. It was a full employment program for particle physicists."

A full professor of theoretical physics at Utrecht for the past 23 years, 't Hooft has continued to justify his reputation as a leading light, making many great advances in the discipline, Lane says. Some of 't Hooft's recent research projects have concerned magnetic monopoles, microscopic black holes, and other fundamentally important properties of gauge theories, which hold that forces among elementary particles are mediated by the exchange of "gauge fields."

"Last October, right after the prize was announced, I called Gerard and asked if he would be willing to give this named lecture," recalls Lane, a friend and colleague of 't Hooft's since the early '70s. "And he said, 'Well, I'm a little busy, but yes,' which just shows his warm and friendly character. Gerard spent the fall semester of 1988 as a visiting professor in the physics department, and he has many friends here."

The memorial lecture series was named by Dean S. Edmonds, Jr., CAS professor emeritus of physics, in honor of his father. Dean S. Edmonds, Sr., was a Boston intellectual property attorney who secured the first patent for FM radio.

The lecture will take place at 3:45 p.m. on Tuesday, April 25, in Room 107 of the Metcalf Science Center, 590 Commonwealth Ave. There will be a brief reception outside the room at 3:20. The lecture and reception are free and open to the public. For more information, call 353-2600.