During a yearlong fellowship at the University of Turin in Italy, John Michael Kosterlitz was working on a particular physics model—a precursor to string theory. Just as he was about to submit his research to an academic journal, another research group at a different university beat him to the punch. Kosterlitz shifted gears and focused on a different problem. He solved it, and right when he was ready to send in his work, it happened again—an advance copy of the other group’s paper appeared on his desk, describing the solution to his problem.

At that moment, Kosterlitz decided he had to take a different approach. There was too much competition in his field—high energy physics—and he was getting pushed out. Kosterlitz didn’t know it then, but the decision to try something new would lead to him sharing the 2016 Nobel Prize for Physics with research partners David J. Thouless and F. Duncan M. Haldane.

Kosterlitz recalled this story on Thursday before an audience of students, faculty, staff, and alumni as part of the College of Science Distinguished Lecture Series. Arun Bansil, University Distinguished Professor in the Department of Physics at Northeastern, introduced Kosterlitz. Bansil’s research team at Northeastern focuses on theoretical condensed matter physics.

“My own group here, like so many groups all over the world, has been greatly impacted by the work of Dr. Kosterlitz,” Bansil said.

For the research that would eventually earn them a Nobel Prize, Kosterlitz, Thouless, and Haldane worked together to explain a puzzling experiment. Picture a crystal with a flat surface covered in a thin film of helium only a couple of atomic layers high. A widely accepted physics theory says that as the crystal’s mass increases, so does the film’s resonant frequency, or the rate at which it moves back and fourth on the crystal’s surface. But at some point, scientists observed that the trajectory deviated. The helium breaks away and doesn’t move with the crystal anymore. And this was completely unexplained by the accepted theory.

“Which do you believe?” Kosterlitz asked. “The rigorous mathematics or the observation?” He and his colleagues chose the latter. Their work on this enigma is what earned them the Nobel Prize for “theoretical discoveries of the topological phase transitions and topological phases of matter,” or as the concept is now known, the Kosterlitz-Thouless transition.

Kosterlitz encouraged budding scientists in the audience to remember his story of frustration at the beginning of his career. “Never give up. It’s always worth pushing on,” Kosterlitz said. “You never know what’s going to happen.”