Mark B. Wise, Caltech's John A. McCone Professor of High Energy Physics, passed away on July 10, 2026. He was 72.
Wise, a particle physicist whose research focused on the fundamental constituents of matter and their interactions, played a key role in the development of the "heavy quark effective theory," a tool that has allowed physicists to make precise predictions in the study of strong interactions within the nuclei of atoms—also known as the strong force. The strong force serves as the subatomic "glue" that binds quarks together into protons and neutrons, and then those protons and neutrons together to form atomic nuclei. In addition to other key contributions to theoretical particle physics, Wise also developed important theories in the field of cosmology.
"Mark was an amazing physicist and one of those rare individuals who cared deeply about the division and Caltech. He was always there to help when needed," says Fiona Harrison, the Harold A. Rosen Professor of Physics and formerly the chair of the physics, mathematics, and astronomy division from 2015 to 2025. "Throughout his career, he led many of our most important efforts, from the committee that hires new faculty to strategic planning. His wisdom, his consistent commitment to scientific excellence, and his integrity shaped many important decisions. The legacy of his contributions will live on for generations."
Maria Spiropulu, the Shang-Yi Ch'en Professor of Physics at Caltech says Wise was "brilliant and endlessly generous with his time to me and to my students for more than a decade. His loss is immense."
John Preskill, the Richard P. Feynman Professor of Theoretical Physics and Allen V. C. Davis and Lenabelle Davis Leadership Chair of the Institute for Quantum Information and Science (IQIM), also remembers Wise's brilliance and generosity.
"He was a tenured professor at the young age of 31, within two years of arriving at Caltech, while other places were trying to steal him," says Preskill, who first met Wise while they were both junior fellows at Harvard University. "The students loved him. He was funny, and that made him approachable. The students paid attention because they didn't want to miss the jokes." In fact, Wise's students started an X account in 2010, @MarkWiseSays, where they would write down funny things he said while teaching.
Caltech's Cliff Cheung, professor of theoretical physics and director of the Leinweber Forum for Theoretical Physics, says, "Mark was a titan of theoretical physics whose towering achievements were matched only by his unbounded humility, kindness, and generosity to all. He nurtured generations of scientists who would go on to shape our field, always leading by example with his incisive intellect, infectious enthusiasm, and wicked sense of humor. We will all miss him dearly."
Wise was born in Montreal, Quebec, Canada, on November 9, 1953. He grew up with his mother, younger brother Mitchell, and older sister Jenna, as he describes in his oral history interview with the American Institute of Physics (AIP) in 2021. In the interview, Wise says that, growing up, he did not do well in school.
"I was a terrible student. I wasn't failing overall but certainly was not a good student. And, in fact, my mother told me that in grade nine the guidance counselor recommended to her that I don't go to high school, that I pursue a trade or something of that ilk. I don't think I have a tremendous amount of natural ability in the sciences. We grew up poor because of the circumstances I mentioned [growing up with a single mom]. … [I]n grade nine, I realized I have to do something with my life." Wise says he started reading books on science as well as science fiction books by Isaac Asimov and began to like physics.
"When I got to high school, there were some very good teachers, and I got engaged more and just got better and better by working hard at it," he said. "I had excellent physics teachers as well. Ms. Falona was a very inspirational teacher for me. I like to mention their names because I don't think they get enough credit."
Wise received his bachelor's and master's degrees from the University of Toronto in 1976 and 1977, respectively, and a PhD from Stanford University in 1980. At Standford, Wise did theoretical research in particle physics at the Stanford Linear Accelerator (SLAC) under his advisor Fred Gilman, a professor of theoretical physics emeritus at Carnegie Mellon University.
"He was a spectacular advisor," Wise recalls in his oral history interview. "He gave me a first project almost right away, and I think that's very important not to leave new students hanging. It was a good project and doable."
Wise later worked as a junior fellow in the Harvard Society of Fellows at Harvard University from 1980 to 1983. Together with Preskill and Nobel Laureate Frank Wilczek, Wise proposed that a hypothetical particle called the axion was, in fact, the sought-for particle underlying dark matter, a mysterious substance making up 85 percent of all matter in our universe. Today, researchers are still searching for axions.
"We pointed out that these particles could be produced in the early universe to account for dark matter," Preskill says. "The paper is highly cited, but most of the citations came in the last five years, now that people are doing more experiments to search for axions. This is the work Wise and I did together that we were most proud of."
Wise was recruited to the Institute in 1982 by Caltech Nobel laureates Murray Gell-Mann (1929-2019) and David Politzer, the Richard Chace Tolman Professor of Theoretical Physics at Caltech. Politzer won the Nobel Prize in Physics in 2004 for solving problems related to the strong force; Wilczek and David Gross shared the prize for making the same discovery independently. Politzer's pivotal research helped solve problems with Gell-Mann's theory of the strong force, called quantum chromodynamics or QCD, rendering it a viable and hugely important theory still in use in physics today.
"When Mark arrived, it was clear he was far better versed than anyone in what was happening in particle physics," Politzer says. "You could ask him about anything, he'd have an opinion, and he'd tell you what was going on. He kept that up until his dying day. He was always current—reading all the papers and knowing what every experiment was doing. There aren't many people like that in the field, and only a few of them are also as innovative as he was."
In his oral history, Wise talks about deciding between faculty position offers from UC Berkeley and Caltech. He said both had a high caliber of faculty and graduate students, but
it was the housing plan more than anything else that convinced him to come to Caltech. "At Caltech, I could afford a house I wanted. … I got married as an undergraduate, and, by then, I had two children. They were born in Boston. I grew up in an apartment, so I really wanted to have a house when I became a professor."
Wise's greatest scientific legacy is his 1989 work, with Nathan Isgur, on heavy quark effective theory. Before this theory, making calculations and predictions about particles containing heavy quarks using the QCD theory was unwieldy. Wise and Isgur realized that they could take advantage of the fact that some of the quark types—the bottom and charm quarks—were much heavier than the other lighter quarks (there are six types of quarks). By lumping the heavy quarks together in calculations, Wise and his colleague found a way to simplify the problem.
"It was agony to calculate using QCD in situations involving light and heavy quarks simultaneously before we had Mark's theory," Politzer says. "Mark's theory packaged the physics into a set of rules so that a calculation just comes out mechanically. The theory made experiments more accessible and is still widely used today."
Wise was drawn to the fundamental questions about how nature works, Preskill says. "He was good at recognizing a problem you can solve, where the result would tell you something useful, for example, about an experiment you should do."
Ben Grinstein, a professor of physics at UC San Diego and a longtime collaborator of Wise's, recalls that he could be tough. "He was very demanding of himself, and he expected his collaborators to be equally demanding. He would also jump around a lot in topics of interest and had an extraordinary nose for good physics that had an impact. That's not something that comes easily. He had a gift," says Grinstein, who first met Wise while a graduate student at Harvard and later worked with him as a Caltech postdoc.
Wise took great care to give his students good ideas to work on, and students loved him as a teacher. One of his undergraduate students, Vineer Bhansali (BS, MS '87), went on to become a lifelong friend. Bhansali says that Wise even stood in for his parents when they could not make it to his graduation. "Mark Wise, Tom Tombrello [formerly the Robert H. Goddard Professor of Physics at Caltech], and David Politzer were my 'parents' at graduation and helped me celebrate with the graduation lunch at the Athenaeum."
In 2000, after Bhansali took over as head of analytics and research at an investment management firm, PIMCO, in Newport Beach, he invited Wise to join him in financial research. "Mark immediately agreed and would drive down a couple of times a month and work on finance with me." Among several finance projects, the two wrote "a beautiful paper on the asymptotic behavior of mortgage prepayments," Bhansali said.
"Over the years, what started as a chance introduction of a freshman and a legendary physicist morphed into a lifelong friendship and relationship," Bhansali said. "Of course, he was a humble person. But, above all, he was one of the best human beings I have ever known. He will be missed."
Wise joined the Caltech faculty as an assistant professor in 1982, became associate professor in 1984, professor in 1985, and McCone Professor in 1992.
"I first met Mark in about 1980," says Barry Barish, Ronald and Maxine Linde Professor of Physics, Emeritus at Caltech who was co-awarded the 2017 Nobel Prize in Physics for his seminal work on LIGO. "For 16 years, he was the principal investigator of Caltech's high energy physics program: the combined experimental and theoretical grant, and then the theory program until the end of his life. I have led large projects for decades—I know what that job weighs. Mark carried it so steadily that most people never saw the weight at all. The heaviest responsibilities, held with quiet scientific leadership—that was Mark."
Wise was also a member of the Department of Energy (DOE) P5 panel in 2013 that "set the national course for high energy physics and gave us the program we have today as a nation," Spiropulu says. "His help was invaluable in coordinating our program with Fermilab."
"In the classroom, he paid students a quarter for every correct answer—an economy of encouragement he ran for years out of his own pocket, 25 cents at a time," Spiropulu recalls. "His students answered in kind: Without telling him, the undergraduates of Dabney built him in LEGO—a small white-haired figure at a blackboard, mug in hand, lecturing to eternity. Institutions confer medals and chairs. Students build you out of LEGO only if they love you."
He was a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences. In 2001, Wise was awarded the J. J. Sakurai Prize for Theoretical Particle Physics by the American Physical Society.
"Mark was a distinguished scientist and a dedicated teacher and mentor, deeply committed to his students and postdoctoral scholars. He was also a kind and generous colleague whose counsel I always valued. I will miss him," says Hirosi Ooguri, the Fred Kavli Professor of Theoretical Physics and Mathematics and the Kent and Joyce Kresa Leadership Chair of Caltech's Division of Physics, Mathematics and Astronomy.
He is survived by his wife, Jackie, his children Barry (and his wife, Marissa) and Jonathan (and his wife, Diana), his grandchildren Leo, Alex, and Jacob, his sister Jenna Hofbauer, and his bother Mitchell Wise.
Mark Wise with colleagues at "50 Years of the Quarks," a conference marking the 50th anniversary of Murray Gell-Mann's introduction of the quark model. The conference was hosted by Caltech's High Energy Theory Group in December 2013.
Credit: Hirosi Ooguri
A photo from Mark Wise's 60th birthday party. "In lieu of a fancy conference, as would have been expected given his immense stature, we all went curling," says Cliff Cheung.
Mark Wise at the blackboard.
Credit: Clara Murgui, Caltech
Mark Wise and Hirosi Ooguri at Caltech's Commencement in 2025. "Mark was an exceptional mentor, and commencement was a joyful occasion for him and for his students," Ooguri recalls.
Credit: Hirosi Ooguri
Mark Wise, Carolee Joyce Winstein, Kip Thorne, and Maria Spiropulu at a Machine Learning for Jet Physics conference in 2025.
Credit: Maria Spiropulu
Mark Wise and friends celebrating the wedding of John Preskill's daughter in 2016. Left to right: John Preskill, Mark Wise, Jackie Wise, Roberta Preskill, Carolee Joyce Winstein, and Kip Thorne.
Credit: Olivia Leigh
In this painting by Clara Murgui, formerly a Burke Fellow at Caltech, Mark Wise crosses a rope bridge from the Downs-Lauritsen Building to the Ginsburg Center for Quantum Precision Measurement to visit his longtime friend and collaborator John Preskill, while braving the hazards of his imagined "Jurassic Tech." Wise asked Murgui to create the illustration for a characteristically humorous message to Caltech's leadership, in which he advocated the rope bridge as a less costly yet fully functional alternative to the planned enclosed bridge. Murgui is now a staff scientist at CERN.
Credit: Clara Murgui
This photo was taken during a class taught by Mark Wise in which he transformed the lecture into a "Who Wants to be a (Physics) Millionaire" contest, complete with actual Romanian currency. "The photos are a little blurry as Mark was bouncing around the room so much. Mark went to a lot of effort to make this lecture work," says one of Mark's graduate students who was at the lecture, Donal O'Connell (PhD '07), now a professor of physics at the University of Edinburgh.
Credit: Árdís Elíasdóttir
Mark Wise and former Caltech postdoctoral scholar Jennifer Ngadiuba.
Credit: Maria Spiropulu