Michael Kosterlitz, winner of the 2016 Nobel Prize in Physics, met with students from the physics department during a town hall event.

PROVIDENCE, R.I. [Brown University] — During a town hall meeting in Barus and Holley on the evening of Thursday, October 27, Brown students and faculty welcomed Professor Michael Kosterlitz back to College Hill for his first visit to campus since being named winner of the 2016 Nobel Prize in Physics earlier this month.

Kosterlitz is on a semester-long sabbatical from Brown, working abroad in Finland and South Korea, before he returns to the University in January. During a brief trip home this week, Kosterlitz met with colleagues in the physics department as well as University President Christina Paxson, Provost Richard Locke and Dean of the Faculty Kevin McLaughlin.

At Thursday’s town hall event, Kosterlitz fielded questions from students, faculty and other members of the Brown community.

“I never thought it would actually get this far,” Kosterlitz said of the work he did with physicist David Thouless that earned him the prize. “David and I knew we had done something good when we did the initial work because we were able to solve a problem that had been bothering physicists for quite some time.”

That work provided a theoretical understanding of phase changes in ultra-thin, two-dimensional systems. Phase changes in normal matter — when a gas condenses into a liquid or a liquid freezes to a solid — are well understood. But how phases changes work in two-dimensional materials wasn’t known until the work of Kosterlitz and Thouless. The pair shared the prize with another physicist working in this area, Duncan Haldane.

Kosterlitz and Thouless’s theory of phase transitions, known as the K-T transition, has informed the understanding of a range of exotic materials, including topological insulators — materials that conduct electricity on their surfaces but act as insulators in their bulk. Materials like this could one day form the backbone of next-generation electronics devices and quantum computers.

Kosterlitz joked that his entrée into the theoretical side of physics came out of frustration with the experimental side.

“It seemed like whenever I went into the laboratory, things just stopped working,” he said. “I decided that it’s best for everybody if I don’t go near a laboratory, so that’s why I became a theorist.”

However, his prize-winning work in condensed matter physics wasn’t his initial focus. Kosterlitz launched into high-energy physics, working with a precursor to what is now known as string theory. That work didn’t prove rewarding or particularly innovative.

“I had been doing long tedious calculations, and I didn’t seem to get any return from it,” Kosterlitz said. “Two or three times, I had just finished a calculation and was about to write it up and send it out for publication when a preprint arrived on my desk doing exactly what I had just done.”

One of those preemptive papers happened to have been written by Chung-I Tan, professor and former chair of physics at Brown.

“So I have to thank him for my transition from high-energy physics to condensed matter,” Kosterlitz said.

A first-year student planning to concentrate in astrophysics asked Kosterlitz on Thursday what direction he thought physics would take in the coming years.

Heesoo Kim, a Brown sophomore, takes her turn speaking with Brown's newest Nobel Laureate.

“To me, physics is a never-ending thing because there are always new problems,” he said. “Even if one thinks that physics is dead, as was said some years go, there are always new problems. Just look out your window in the morning sometimes, you’ll see lots of problems out there.”

Another student asked Kosterlitz what aspect of his career has been the most rewarding.

“The fun I’ve had doing it,” he answered. “Most of the problems I’ve worked on, I have found fascinating and fun. Of course, getting recognition and getting this prize is wonderful, but it’s not the main thing.”

Gang Xiao, chair of the physics department, reminded students of the opportunity they have to work closely with a Nobel Laureate.

“The difference between our University and other universities is that here Nobel winners teach both undergraduate and graduate courses,” he said. “So we grant an opportunity to work with Professor Kosterlitz and use him as a mentor.”

Kosterlitz will return to the classroom next semester, teaching statistical mechanics to graduate students and advanced undergraduates.