Hirosi Ooguri, the Fred Kavli Professor of Theoretical Physics and Mathematics at Caltech, will become the next chair of the Division of Physics, Mathematics and Astronomy (PMA) on August 16, 2025. Ooguri, who has served as the director of the Walter Burke Institute for Theoretical Physics since its founding in 2014, is a leading theorist in string theory, which attempts to unify the microscopic laws of subatomic particles with the macroscopic laws of gravity. His work has provided key insights into related topics such as black holes, particle physics, dark energy, and advanced theories of math.
"I'm delighted that Hirosi has agreed to serve as division chair," says Caltech Provost David A. Tirrell. "Hirosi is a distinguished scientist and a gifted educator whose work spans much of the broad range of inquiry that characterizes our Division of Physics, Mathematics and Astronomy."
Ooguri received his bachelor's degree from Kyoto University in 1984 and his PhD from the University of Tokyo in 1989. He joined the Caltech faculty in 2000. Among many honors, Ooguri has received the Medal of Honor with Purple Ribbon from the emperor of Japan and the Eisenbud Prize for Mathematics and Physics from the American Mathematical Society. He is a fellow of the American Academy of Arts and Sciences and the American Mathematical Society. Ooguri's popular science books have sold more than 400,000 copies, and his Introduction to Superstring Theory was awarded the 2014 Kodansha Prize for Science Books. He also served as a science advisor for a three-dimensional dome movie produced by Japan's National Museum of Emerging Science and Innovation.
In addition to his contributions on the Caltech campus, Ooguri helped establish the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo in 2007 and served as its director from 2018 to 2023. He was also the president (2016 to 2019) and chair of the board (2021 to 2024) of the Aspen Center for Physics.
"For the past 25 years, Caltech has supported my research and teaching, helping me grow professionally in this remarkable academic environment," Ooguri says. "While the times ahead may be challenging, I will do my best to help us emerge stronger."
Ooguri succeeds Fiona Harrison, the Harold A. Rosen Professor of Physics, who currently holds the Kent and Joyce Kresa Leadership Chair of the PMA division. Harrison served as the PMA chair for the past decade, overseeing the hiring of 20 faculty members, the transformation of the former Sloan Laboratory into Linde Hall, the relocation of the American Institute of Mathematics (AIM) to Caltech Hall, and the start of construction on the Ginsburg Center for Quantum Precision Measurement. During Harrison's tenure, the Brinson Exploration Hub was established, funding was secured for the development of new astronomy instruments, and Caltech researchers made hundreds of discoveries, including the first direct detection of ripples in space-time called gravitational waves in 2015—a finding that would, in 2017, earn two Caltech professors the Nobel Prize in Physics.
During her time as chair, Harrison also served as the principal investigator for two NASA missions: the ongoing NuSTAR mission, an X-ray telescope probing the secrets of black holes, and the UVEX mission, which will use ultraviolet light to survey stars and galaxies.
"Fiona has provided extraordinary leadership for the PMA division for the last decade," Tirrell says. "Her wisdom, vision, and sound judgment have transformed the division faculty, enhanced its physical facilities, and enriched its programs of education and research."
Ooguri says, "I am honored to succeed Fiona Harrison and grateful for the opportunity to serve Caltech in this new role."