When he was a kid, Shaun Pexton would pore through popular science magazines like New Scientist and Scientific American to keep up with the latest advances in astrophysics or biology. But by the time he was 12 or 13, one particular topic really started to fire his imagination: quantum mechanics.
He wasn’t quite sure how it might be relevant to his life at the time, but there was something exciting about this field which evoked scientific mysteries — the idea of quantum “entanglement,” for instance, a phenomenon so critical to the emerging world of quantum computing — that seemed almost too impossible to grasp.
“I would always try to find the page that had the word ‘quantum,’” remembers Pexton, a Yale senior from Silliman College. “The magazine would have these articles with almost magical diagrams that showed these cool processes. To me it really was magic because it was so distant from what I saw every day. It really pulled me in, in a very real sense.”
For Pexton, who was born in Hong Kong, grew up in Singapore, but spent his high school years in the U.K., these mysteries became ever more engrossing, and to better understand them he expanded his reading to journal articles and textbooks. When it came time for college he turned his attention to Yale, a university steeped in quantum history, where pioneering researchers have imagined and built the infrastructure for the next generation of quantum technology — and a seedbed for tech industry talent.
Once he got here, it was like being in a quantum candy store.
And he’s made the most of every opportunity. A double major in Applied Physics and Computer Science, Pexton has taken graduate-level courses with several of the quantum pioneers he admired as a kid. He has collaborated with some of them on research projects (on both the theoretical and hardware sides of quantum). And he’s turned his work into multiple papers — including one in the top journal in quantum science — plus a pending patent.
His research has focused specifically on a key hurdle facing quantum computing – the challenge of correcting errors. In standard computers, the data stored inside the computer is largely insensitive to its surroundings. In quantum computers, however, a slight environmental change for bits of quantum information — known as qubits — can trigger a cascade of errors.
When he learned that Aleksander Kubica, a quantum theorist and rising star in quantum error correction, was planning to come to Yale in 2024, Pexton immediately sent him an email, expressing an interest in working with him. Indeed, Kubica welcomed Pexton to join his lab, and for the past two years he’s worked with him on various projects.
Through this work, Pexton hopes to convert elegant quantum theories into systems that can actually work. Quantum error correction, he says, is often framed as a question of abstract mathematics. But his aims are decidedly practical: “I ask, ‘Can we actually implement this on a physical system?’” he says. “What does that look like? What are the…hardware trade-offs?”
Shaun Pexton, who has played tenor sax since he was a kid, collaborated with a DJ to perform a jazz+EDM set.
As important as the university’s global reputation in quantum has been to Pexton, however, it’s not the only reason he was drawn to Yale. He was also intrigued by, well, everything about the university culture. A jazz musician since he was a child, he has played with the Yale Jazz Ensemble, which opened doors to the wider jazz community beyond campus, including in New York City. And he’s taken advantage of academic and extracurricular opportunities that have helped him to widen his lens intellectually, including coursework on the philosophy of science, tech policy, and ethical factors around the rapid rise of AI.
By working with different organizations across the Yale and New Haven communities — including with Code Haven, a student-run organization that works with local kids — he has tried to keep that conversation grounded in the real experiences of real people. “It feels irresponsible to not think about these really important societal questions,” he says.
This fall, he will begin a Ph.D. program at MIT, where he will merge theoretical and practical approaches in the study of error correction.
“We’re at a stage now where people are doing really exciting things with quantum computers — the things that felt like magic to me as a kid,” he says. “But we’re also at the bottleneck. Error correction is what stands between a beautiful theory and machines that actually work at scale — and that’s exactly where I want to be.”
“I want to work shoulder-to-shoulder with experimentalists because every new piece of hardware could open up possibilities we’d never dreamed of. That’s the frontier.”
