On those rare days when it’s actually nice outside, you’ll find students throwing a Frisbee (or if you’re a stickler for the official generic term, a disc) around Deering Meadow or the Lakefill. Other students might be studying for their classes, but if you’re like Professor Eric Zaslow, you can have it all. In addition to being a professor, Zaslow is internationally ranked in Ultimate, a sport where players score points by catching a disc in their opponent’s end zone.

Zaslow teaches in the math department, but he also has a deep interest in physics. He received his PhD in physics from Harvard University and now teaches at Northwestern, studying string theory.

“I’ve always been on the fence between math and physics, and string theory is a very mathematical branch of physics,” Zaslow said. “The idea is to explain the core theories, especially to unify the theory of gravity, Einstein’s theory of gravitation, general relativity with the theory of elementary particles, quantum theory. Those two theories clash, and they are not consistent with one another, but string theory aims to unify the two.”

Zaslow uses mathematics to find parallelism in different structures. He applies ideas of parallelism from physics to mathematics, and his research focuses on mirror symmetry, which is an area of mathematical physics. How does Zaslow stay motivated while studying such complex topics?

“I like to delve into the core of a problem, the crux of an issue, and that’s what foundational theoretical physics does,” he said. “I, philosophically, can’t rest easy if I know that the major theories that explain the observed phenomena are incompatible.”

Although his research is theoretical, it could translate into practical applications. A well-known example in the scientific field is how Einstein’s theory of gravitation assisted the development of the GPS. Einstein’s theory shows that the effect of gravity on a satellite differs from the effect of gravity on Earth, and there’s also a difference in how quickly time passes in these two places. To account for this, a GPS will make calculations and adjust according to its satellite clocks.

Despite not having immediate applications, Zaslow is still fascinated by theoretical research, saying that his motivation is “understanding the nature of physical theory and the mathematical structures that it reveals.”

While his physics and math research might not have direct applications now, you can apply the principles from Zaslow’s book, *Ultimate Techniques & Tactics*, to improve your disc saucing skills. And it’s probably sound advice— he’s won national and world championships in multiple Ultimate divisions.

“The players in the sport really drive gender equality. That’s an important part of the sport, and another part of the sport is that it’s self-officiated for the most part. This is an aspect of the sport called ‘Spirit of the Game,’ and it’s kind of just like sportsmanship, but people adopt it pretty well,” said Zaslow. “You play what you love. If you didn’t love the sport, you won’t do it.”