**For over 50 years a[{” attribute=””>MIT, he made fundamental contributions to quantum field theory and discovered topological and geometric phenomena.**

*Dirac Medalist and MIT professor emeritus Roman Jackiw, known for his substantial contributions to quantum field theory, passed away at 83. His discoveries, including the AdlerBellJackiw anomalies, played a key role in shaping the Standard Model of particle physics, significantly impacting various fields such as particle physics, condensed matter physics, and gravitational physics.*

Eminent theoretical physicist andDirac MedalistRoman Jackiw, MIT professor emeritus and holder of the Department of Physics Jerrold Zacharias chair, died June 14 at age 83. He was a member of the MIT physics community for 54 years.

A leader in the sophisticated use of quantum field theory to illuminate physical problems, his influential work on topology and anomalies in quantum field theory (QFT) underlies many aspects of theoretical physics today.

Iain Stewart, the MIT Center for Theoretical Physics (CTP) director and Otto (1939) and Jane Morningstar Professor of Science, says that Jackiw served as an inspiration for what one can achieve as a theoretical physicist. He made profound contributions to physical problems in a wide range of areas, including particle physics, condensed matter physics, and gravitational physics.

Professor Jackiw was a pioneer in the field of mathematical physics, saysNergis Mavalvala, the Curtis and Kathleen Marble Professor of Astrophysics and dean of the MIT School of Science. His imaginative use of quantum field theory shed light on physical problems, including his work on topological solitons, field theory at high temperatures, the existence of anomalies, and the role of these anomalies in particle physics.

SaysFrank Wilczek, a CTP colleague who is the Herman Feshbach Professor of Physics and a 2004 Nobel Laureate, Roman Jackiw had an uncanny knack for identifying curiosities that have grown into fertile, vibrant areas of physics research. His seminal contributions to the theory of anomalies, the interplay of topology with quantum theory, and fractional quantum numbers are a rich legacy which has become central to both fundamental physics and modern quantum engineering.

He was a major, major figure in theoretical physics, Wilczek said to his audience at a conference he attended a day after Jackiws death. Roman was a pioneer in all these subjects, and advanced them greatly, before they became so popular.

He is renowned for his many fundamental contributions and discoveries in quantum and classical field theories. Among his major achievements is the establishment of the presence of the famous AdlerBellJackiw anomalies in quantum field theory, a discovery with far-reaching implications for the structure of the Standard Model of particle physics and all attempts to go beyond it.

Jackiw shared the Dirac Medal with Stephen Adler of Princeton University for their celebrated triangle anomaly, one of the most profound examples of the relevance of quantum field theory to the real world, says the citation from the International Centre for Theoretical Physics. Jackiw made a major contribution to field theories relevant to condensed matter physics in his discovery (with Boston UniversitysClaudio Rebbi) of fractional charge and spin in these theories. They received the medal in 1998 from the International Center for Theoretical Physics in Italy.

Romans style was rigorous and mathematically sophisticated, but not pedantic, saysRobert L. Jaffe, the Otto (1939) and Jane Morningstar Professor of Science, Post-Tenure. After his early groundbreaking work on the triangle anomaly, Roman for many years focused on the application of topological methods in quantum field theory. Although Jackiw was not directly involved in the creation of the Standard Model, which revolutionized physics in the last third of the 20th century, the methods of analysis that Roman invented were often essential to its development.

Bolek Wyslouch, professor of physics and director of MITs Laboratory for Nuclear Science, calls Jackiw a towering figure in theoretical physics one of the leaders that made MIT and the Center for Theoretical Physics worlds first His foundational work was instrumental in establishing the Standard Model of particle physics, one of the most successful theories in physics.

#### Ukrainian roots

Born Roman Volodymyr Yatskiv in Lubliniec, Poland, to a Ukrainian family in 1939, his name was Romanized to Jackiw.

We stayed in Poland until it became clear that the Russians and the Communists would be the dominant force there, and my father didnt want to live under those conditions, recalled Jackiw in anoral history published by the American Institute of Physics.They went to live near his fathers other children, in Austria, and eventually moved to Germany before settling in New York City when Jackiw was about 10.

I was heartbroken to be leaving (Germany), said Jackiw. Its a town called Dingolfing, probably known these days to car buffs because BMW started in Dingolfing, or had one of its original factories in Dingolfing.

In New York, he was educated by Xaverian monks in junior high, and Christian brothers in high school. I became convinced I wanted to be a physicist after reading [George] Gamows One Two Three Infinity, Jackiw recalled. It describes people doing things that I find fascinating and wanted to do. It was actually a leap of faith because I didn’t get to make them until graduate school.

After graduating from Swarthmore College in 1961, where he majored in physics with majors in the history of science and mathematics, he went on to Cornell University, where he worked with professors Hans Bethe and Kenneth Wilson and received his Ph.D. 1966. Jackiw recalled working on a thesis that went against Wilson’s advice.

He wanted me to use the renormalization group to find the high-energy behavior of form factors in electrodynamics. It turns out that the renormalization group doesn’t check for that, but other approximations can be used to solve that problem, and I did. My thesis has been published and is still cited.

He had wanted to work with Bethe, but Bethe was into nuclear physics while Jackiw was more interested in particle physics. However, Bethe asked him to co-author a textbook on quantum mechanics: Intermediate Quantum Mechanics. The popular book, newly revised in 2018, has been the basic introduction to the application of quantum mechanics to atomic physics for many years.

From 1966 to 1969 he was a junior fellow at Harvard University. In his sophomore year, he went to[{” attribute=””>CERN, working with John Bell. I discussed current algebra a lot with him, Jackiw recalled, and then we fell into the problem of the decay of the neutral pion into two photons, which was a puzzle at that time, and we studied the properties of the axial vector current and discovered the axial vector current anomaly, and wrotea paper, which is my most cited paper and also John Bells most-cited*Particle Physics*paper, in fact.

At the time, theory seemed to predict that the neutral pion could not decay into two photons, but the decay had been observed in experiments. With the BellJackiwAdler anomaly, clarified later by Stephen Adler, they were able to explain the observed decays theoretically by adding an anomalous term resulting from the divergences of quantum field theory, according to anarticle in*Physics World*.

In his final year at Harvard, Jackiw had been working with other theorists at MIT. Physics professorsSteven WeinbergandSergio Fubini, together with physics department headVictor Weisskopf, helped to initiate Jackiws long career as a professor at the Institute, which began in 1969. In his first years at MIT, Jackiw and David Gross showed that cancellation of gauge anomalies implied an interesting connection between fermions in the Standard Model in particular, that fermions in two classes, those which are strongly interacting and those which are not, have to appear the same number of times. Over the years this cancellation continued to suggest the existence of new fermions before they were observed.

Jackiw held visiting professorships at Rockefeller University in 1977-78, at the University of California Los Angeles and the University of California at Santa Barbara in 1980, and at Columbia University in 1989-90. He became an emeritus professor in 2013.

#### An unusual kind of greatness

Jackiw had said he had two bodies of work. The first were mathematical investigations which fit Diracs criterion of beauty and have physical application because they are beautiful, like fractional charge phenomenon that I mentioned earlier, and like the anomaly phenomenon, like the Chern-Simons terms which I introduced with the help of [Stanley] Deserand students and later explored with So-Young Pi. Pi, currently a professor emeritus of physics at Boston University, is a distinguished physicist who co-authored many of Jackiws papers and is Jackiws widow.

But on the other hand, I also did a kind of methodological investigation, which was not necessarily original, but applied existing patterns to a new context. Such as, for example, understanding how to do finite-temperature quantum field theory and finite-temperature relativistic quantum field theory, taking up what they do in condensed matter physics and quantum field theory non-relativistic approach to matter physics condensed at finite temperature.

Jackiw was known for working on mathematically intricate physics without an application in mind. What I’ve always liked is doing work that feels dark but interesting, and then decades later it catches on, he said.

Roman Jackiw was a giant of theoretical physics, but of a somewhat unusual kind, recalls Daniel Harlow, the Jerrold R. Zacharias, career development associate professor of physics at the Center for Theoretical Physics. He rarely worked on the same thing as the others, and indeed if something he was doing started to catch on, he often turned to something else. Yet her ideas of him had a way of growing: he let them hang around, and then a decade or two later everyone else realized that he really had something figured out.

For example, Harlow once asked him why he studied gravity in two dimensions of spacetime. His response: Well, everyone else was thinking about gravity in more than four dimensions, so I figured I’d see what happens in less than four.

His work on low-dimensional gravity from the 1980s has really taken off in the past five years, Harlow says. His influence will be felt both here at MIT and around the world for generations.

David Kaiser, a physics professor and professor of the history of science at Germeshausen, says that while working with a CTP graduate student, it seems that every other day we find that Roman had first published on this or that piece of what we’re looking for. to understand, many years ago, in greater generality and with much more elegance than we ever aspired. He and his work remain a great inspiration to us.

Indeed, in addition to Jackiws’ celebrated work on anomalies, other important examples of his contributions include providing the first example of charge and spin fractionation with solitons, elucidating the periodic vacuum structure of non-Abelian gauge theories forming the nucleus of the Standard Model of particle physics, launching the use of quantum field theory for the rigorous study of finite-temperature systems and determining the nature of Chern-Simons terms for both gauge and gravitational theories.

This wide range of research has influenced countless others. To appreciate Roman’s impact on theoretical and mathematical physics, look at how often people refer to him by name in their papers, with examples including Adler-Bell-Jackiw anomalies, Jackiw-Teitelboim gravity, quantization of Fadeev-Jackiw, the ansatz Jackiw-Nohl-Ressen and the models Jackiw-Rossi, Jackiw-Rebbi and Jackiw-Pi, says Stewart.

Roman had more than 30 PhD students, including Estia Eichten (Cornell), Joseph Lykken (Fermilab), and Andrew Strominger (Harvard); he was a highly successful mentor to generations of doctoral students who formed a school of theoretical physics focused on using sophisticated mathematical methods to explore the physical content of quantum field theories, Jaffe recalls.

#### Other awards and recognitions

From 1969 to 1971, Jackiw was honored as an Alfred P. Sloan Research Fellow and from 1977 to 1978 as a John Simon Guggenheim Memorial Fellow. In 1995 Jackiw received the Dannie Heineman Prize for Mathematical Physics from the American Physical Society for his imaginative use of quantum field theory to shed light on physics problems, including his work on topological solitons, high-temperature field theory, the existence of anomalies and the role of these anomalies in particle physics. In 2007 he was awarded the Bonnor Essay Prize by Queen Mary University of London.

He was a member of the American Academy of Arts and Sciences, the American Physical Society and the National Academy of Sciences, and a foreign member of the Ukrainian National Academy of Sciences. Honorary degrees have also been conferred by the University of Turin, Italy; Uppsala University, Sweden; the Kyiv Bogolyubov Institute, Ukraine; and University of Montreal, Canada.

Professor Jackiw has written six other books: Lectures on Current Algebra and its Applications (with S. Treiman and D. Gross); Dynamical Gauge Symmetry Breaking (with E. Farhi) 1982; Shelter Island II (with N. Khuri, S. Weinberg and E. Witten) 1985; Current Algebra and Anomalies (with S. Treiman. B. Zumino and E. Witten) 1985; Various topics in theoretical physics and mathematics, 1995; and Lectures on fluid dynamics, 2002.

I have immense respect for his legacy and success and greatly appreciate the doors he has opened for all of us, says Stewart.

He is survived by his wife, So-Young Pi, and three children: Stefan Jackiw, violinist; Nicholas Jackiw, software designer; and Simone Ahlborn, a teacher at Moses Brown School in Providence, Rhode Island. The funeral will be private.

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