Sidney Richard Coleman, a member of the Harvard faculty for 43 years and a giant of theoretical physics, died on Nov. 18 after a five-year struggle with Parkinson’s disease. He was 70.

Nobel Prize winner and former Harvard colleague Steven Weinberg, now professor of physics and astronomy at the University of Texas, said, “I always thought that Sidney Coleman understood modern theoretical physics better than anyone else. One of the many issues that he was able to illuminate was the process by which the universe makes a transition from an apparently stable state to a state of lower energy. According to the groundbreaking work of Coleman and his students, bubbles of ‘true vacuum’ appear here and there in a background of ‘false vacuum.’ This process is now believed to have occurred several times in the early history of our universe, pretty much as described by Coleman.”

For 30 years, Coleman taught Physics 253, “Quantum Field Theory,” to a standing-room-only crowd. His legendary lectures, known for their clarity, insight, and dry wit, inspired a whole generation of young physicists.

He had his eccentricities, however, and everyone has a favorite “Sidney story.”

In the 1960s, he threatened to sue a student publication for calumny, because they said he taught physics in a purple polyester suit. “It was wool,” he sniffed.

A denizen of the old Harvard Square, before his marriage Coleman could usually be found long past midnight at Hayes-Bickford cafeteria arguing physics with his friends. Famously nocturnal, he refused to teach a 9 a.m. class because, he said, “I can’t stay up that late.”

Coleman was born on March 7, 1937, in Chicago. He was the son of a businessman who died when the boy was 9. He, his mother, and his infant brother fell on hard times and lived in a tough neighborhood in Chicago. According to his brother, Robert L. Coleman, in the 1940s, Sidney became interested in the building of the atomic bomb and declared his ambition to become a physicist. In high school, he and a friend built a primitive computer and won the Chicago Science Fair.

He developed a passion for science fiction, and, at 18, became a founder of Advent: Publishers, which publishes critical works about science fiction. Greg Benford, a well-known science-fiction writer and another of the founders, remarks that Coleman’s reviews of science fiction often influenced the writers and that sci-fi perhaps influenced the titles of Coleman’s scientific articles, for example the renowned “Why There Is Nothing Rather Than Something: A Theory of the Cosmological Constant,” published in Nuclear Physics B in 1988.

Coleman graduated from the Illinois Institute of Technology in 1957 and went to the California Institute of Technology (Caltech), where he studied with Richard Feynman and Murray Gell-Mann, who directed his thesis. In 1961, at the age of 26, Coleman came to Harvard as the Corning Lecturer and Fellow. He received his Ph.D. from Caltech in 1962, became assistant professor in 1963, Sloan Fellow in 1964, and associate professor in 1966. In 1969, he became a professor of physics and, in 1980, the Donner Professor of Science. He held numerous visiting professorships and received the Dirac Medal and the Dannie Heineman Prize. He was a fellow of the American Academy of Arts and Sciences and the National Academy of Sciences.

In 1985, Coleman’s book “Aspects of Symmetry: Selected Erice Lectures” was published, replacing the treasured but tattered sheaf of class notes that his students had carried around for years.

Over the course of his career, Coleman supervised 40 doctoral students. In addition, as Arthur Jaffe, Harvard’s Landon T. Clay Professor of Mathematics and Theoretical Science, said, “Everybody was Sidney’s student; the faculty were also his students. … He was ‘the Oracle.’ He could synthesize all the ideas he came across and point everybody in a good direction.” In his Nobel Lecture (given in 2004, when he shared the prize in physics with David Gross and Frank Wilczek), H. David Politzer called Coleman “my beloved teacher.” The lecture itself was a paean to Coleman’s teaching method, simultaneously exacting and encouraging, persisting through years of problem solving.

Coleman loved to travel. Erice, Italy; Cargese in Corsica; and Aspen, Colo. — three summer meeting places for physicists — were constants in Coleman’s travels. It is disputed whether it was he or writer/physicist Jeremy Bernstein who coined the term “Leisure of the Theory Class.” He loved to hike. He loved poker. He founded a poker group in 1972, which continued to meet even in his nursing home.

In January 2003, Coleman gave up teaching and took a medical leave. In 2005, to honor him, the Physics Department organized the SidneyFest, which was also a summit of the world’s theoretical physicists. He retired in 2006.

He never lost his sense of humor, his wife recounted. Very recently when the activities director in the nursing home said to her about her husband, “He looks like a nice man,” Coleman piped up, “Looks are deceiving.”

Coleman leaves his wife of 25 years, Diana T. Coleman of Cambridge, Mass., and his brother, Robert L. Coleman of Albany, Calif., and many friends. There will be a memorial gathering at Mount Auburn Cemetery in Cambridge, Mass., in the spring.

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