By Jorge Mercado Wednesday, August 20th, 2025

Gary Horowitz, who joined UC Santa Barbara’s faculty in 1983 and has served as a distinguished professor since 2005 in the Department of Physics, is one of four professors who were recognized with the 2025 Dirac Medal, conferred by the International Centre for Theoretical Physics.

The Dirac Medal, named for Nobel laureate Paul Dirac and always awarded on Aug. 8, is a prestigious honor recognizing people for their groundbreaking work in gravitational physics and string theory. Sharing the 2025 award with Horowitz are physicists Gary Gibbons, Roy Kerr and Robert Wald.

Horowitz is being recognized for his attempt to bridge the gap between the sweeping theory of general relativity to the probabilistic world of quantum mechanics.

“It is a great honor for me to receive this international award,” said Horowitz, a distinguished professor of physics. “I have been fascinated with black holes for most of my career, and am pleased that I was able to use them to take steps toward a complete quantum theory of gravity.”

According to UCSB, Horowitz’s research centers on the classical and quantum aspects of gravity under extreme conditions, such as those inside black holes and the Big Bang — areas where Einstein’s equations break down and a quantum account of gravity is required. 

His work has helped bridge the gap between general relativity and string theory, expanding scientific understanding of spacetime geometry and quantum phenomena.

“We are incredibly proud of Professor Horowitz’s many achievements, including his well-deserved recognition with the 2025 Dirac Medal,” said Shelly Gable, dean of UCSB’s Division of Mathematical, Life and Physical Sciences and the Susan and Bruce Worster Dean of Science. “His work embodies the depth of intellectual curiosity and ambition that characterize our scientific community at UC Santa Barbara, and we are fortunate to count him among our faculty.”

A leading figure in the field, Horowitz has also played a pivotal role in the discovery of Calabi-Yau compactifications, which provide a mathematical framework for connecting higher-dimensional string theory to four-dimensional physical reality.

Moreover, Horowitz helped develop models that integrate black hole physics with quantum theory, including work on the black hole information paradox. 

His collaborations have launched new areas of research: with Andrew Strominger, he explored the gravitational nature of D-branes, contributing to the development of the AdS/CFT correspondence. Later, he worked with Sean Hartnoll and Christopher Herzog to create holographic models of superconductivity, fueling the growth of AdS/CMT as a major research direction.

His 2025 recognition follows his 2023 Einstein Prize from the American Physical Society, which recognized his “fundamental contributions to classical gravity and gravitational aspects of string theory.”

“I’m thrilled to see this recognition of Gary’s remarkable contributions to the understanding of quantum gravity,” said David Stuart, professor and chair of the Department of Physics at UCSB. “This area has long been a strength of the department, attracting outstanding graduate students and postdocs from around the world to study at UCSB with Professor Horowitz and other members of our physics faculty.”

Horowitz earned a bachelor’s degree in physics from Princeton University in 1976 and a doctorate in physics from the University of Chicago in 1979. He first came to UC Santa Barbara in 1979 as a postdoctoral researcher in the Department of Physics. He later conducted postdoctoral research at the Mathematical Institute, Oxford, and served as a member and Albert Einstein Fellow at the Institute for Advanced Study in Princeton.

“I have benefited enormously from the supportive environment at UCSB, including the Kavli Institute for Theoretical Physics and my physics colleagues,” Horowitz said.

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