The theoretical physicist Rafael Sorkin died on September 12, 2026, at his home in Kitchener, Ontario, the Perimeter Institute has announced.
Sorkin joined Perimeter in 2004 and became Emeritus there in 2020. He also held a Senior Researcher position at Syracuse University and was a Fellow of the American Physical Society.
He is best known as one of the main developers of causal set theory, an approach to the emergence of spacetime from discrete points. Nearly a decade before the accelerating expansion of the universe was discovered in 1998, he predicted that causal sets would give rise to an "everpresent" cosmological constant. He also introduced entanglement entropy as a possible explanation for black hole entropy.
To learn more about causal set theory, watch the video, Causal Sets: The Quantum Theory That Predicted Dark Energy
or read A Universe Before Spacetime by Zeeya Merali
Perimeter Institute's full notice, with tributes from his colleagues, here