June 21, 2023
Dear Members of Our Campus Community,
It is with great sadness that I write to share with you that Research Professor and Professor of Physics Emeritus James B. Hartle passed away on May 17.
Dr. Hartle was a world-leading cosmologist and theoretical physicist who helped to found our Institute for Theoretical Physics, now the Kavli Institute for Theoretical Physics, and provided outstanding leadership as its fourth Director, from 1995 to 1997. He was a pioneer in exploring the deepest mysteries of the universe, from general relativity to black holes to quantum gravity. Together with Stephen Hawking, he co-authored the landmark 1983 paper “Wave Function of the Universe,” which has played a vital role in shaping the field of quantum cosmology.
He was an elected member of the National Academy of Sciences and the American Philosophical Society, and a fellow of the American Physical Society and the American Academy of Arts and Sciences. He received numerous recognitions for his extraordinary research achievements and contributions, including a Guggenheim Fellowship in 1988 and the American Physical Society’s Einstein Prize in 2009 for his work in gravitational physics.
Professor Hartle first joined our Department of Physics in 1966, and was known by all for his tremendous dedication to research, teaching, and mentorship. He was selected by his campus peers as our Faculty Research Lecturer in 1992 and delivered a memorable lecture on “The Origins of the Universe.” We are forever grateful for his leadership, his collegiality, and his enduring legacy.
Our hearts go out to his wife, Mary Jo, and their family, and to his colleagues, former students, and friends around the world. In his honor, our campus flag is lowered today.
I am honored to share the following remembrance from his family and our Department of Physics.
James B. Hartle (1939 - 2023)
James Burkett Hartle died peacefully May 17, 2023 in Switzerland, surrounded by his family. He was 83. Despite suffering the devastations of Alzheimer’s disease, he continued his efforts to understand the origin of the universe, how quantum mechanics applies to cosmology, and to ensuring that his theories accurately modeled physical observation. To the end, physics remained his passion and the driving force in his life.
Jim was born in Baltimore, MD in August 20, 1939 to Charles James Hartle and Anna Elizabeth Burkett Hartle. His father was an executive at IBM which, at the time, required frequent family relocation. He attended the Gilman School in Baltimore for five years and then public schools in Ohio and Connecticut. The family returned to Baltimore where he completed his senior year at the Gilman School in 1956.
He completed his undergraduate degree in physics at Princeton University (A.B., 1960), where he met and was mentored by John Archibald Wheeler. He moved to the California Institute of Technology for his PhD where he was advised by Murray Gell-Mann (PhD, 1964). Jim maintained close friendships with both Wheeler and Gell-Mann all their lives.
Turning away from the particle physics he had studied as a doctoral student, Jim became excited by new discoveries in astrophysics and wrote a series of important papers on relativistic stars with Kip Thorne. Thanks to a Sloan Foundation award, he spent a year at the Institute for Theoretical Astronomy at Cambridge University doing research and retraining as a cosmologist. There he met Stephen Hawking, with whom he developed a long-term collaboration. Two of the papers that Jim wrote with Hawking became classics and had a major impact on future research. The first one introduced the Hartle-Hawking quantum state for matter outside a black hole, which plays a fundamental role in black hole thermodynamics. This paper also inspired a new, so-called Euclidean approach to quantum gravity. In the second paper Jim and Hawking applied this approach to cosmology. They introduced the Hartle-Hawking `no-boundary’ wave function of the universe which showed for the first time how the conditions at the big bang origin of the universe could be determined by physical theory. Jim regarded this latter paper as perhaps his greatest contribution to the field.
Throughout much of his scientific career, Jim strived to understand more deeply what it entails to apply quantum mechanics to the universe as a whole and was known as the father of quantum cosmology. In a long-term collaboration with Gell-Mann, Jim developed a formulation of quantum mechanics, known as the consistent histories formulation, that was sufficiently general to describe closed systems like the universe. In later years, he worked with Hawking’s student Thomas Hertog to further explore the implications of the no-boundary wave function. Studying the role of the observer in a quantum universe they introduced a top-down approach to quantum cosmology in which quantum observations retroactively determine the outcome of the big bang, thereby realizing an old vision of Wheeler’s.
Jim spent the majority of his career as a Professor of Physics at the University of California, Santa Barbara (UCSB), a department he found congenial, supportive and inspiring. There he was also a cofounder of the Kavli Institute for Theoretical Physics which brought leading physicists from around the world to UCSB. Jim had affiliations with the University of Chicago, Santa Fe Institute, Cambridge University (Gonville and Caius College; Isaac Newton Institute for the Mathematical Sciences), and Aspen Center for Physics.
His research accomplishments were recognized with the American Physical Society’s Einstein Prize (2009), election to the American Philosophical Society (2016), the National Academy of Sciences (1991) and the American Academy of Arts and Sciences (1989), and an Honorary Doctor of Science from Waterloo University (2004). He was selected to be the Distinguished Faculty Research Lecturer at UCSB in 1992 and the 11th Schrödinger Lecturer at Imperial College London. He also was awarded a John Simon Guggenheim Foundation fellowship in 1988.
In addition to his 188 published papers, he wrote an influential textbook, Gravity: An Introduction to Einstein’s General Relativity, and a recent volume: The Quantum Universe: Essays on Quantum Mechanics, Quantum Cosmology, and Physics in General. Despite his research productivity and his impact, he always felt he had more to do. Indeed, he said that he woke up each morning with new ideas to pursue.
Jim was intellectually curious and an eclectic reader, enjoying learning about ancient Middle Eastern and Mayan archaeology, Sumerian cuneiform, American colonial history, Russian literature, evolutionary biology, and eccentric 19th Century female religious figures. He loved classical music and especially opera, traveled widely and with curiosity, and was a great teller (and reteller) of well-crafted anecdotes and composer of apt and amusing toasts.
Jim is survived by his tightknit family, consisting of his wife, Mary Jo Wheeler Hartle, stepdaughter Sara Wheeler-Smith, and granddaughter Eliza Wheeler-Riewe; his sister Alice Hartle Askey, brother-in-law Robert Askey and nephew and niece James and Elise Askey. In lieu of flowers, contributions to the James and Mary Jo Hartle Graduate Student Fellowship (https://giving.ucsb.edu/Funds/Give?id=348) or the ACLU (https://www.aclu.org) are welcome.
Sincerely,
Henry T. Yang
Chancellor