James Bruce French, a leading theoretical nuclear physicist, died on 1 February 2002 in St. Petersburg, Florida, from complications of an infection following a stroke. He had been a member of the University of Rochester’s physics faculty for 42 years.
Bruce was born in St. Johns, Newfoundland, on 13 November 1921. After completing his BSc in physics in 1942 at Dalhousie University in Halifax, Nova Scotia, he served in the Royal Canadian Navy, for which he performed acoustical studies for antisubmarine warfare. Bruce earned his PhD in physics at MIT in 1948. His thesis research, under the direction of Victor Weisskopf, gave a relativistic calculation of the Lamb shift—essentially simultaneous with Richard Feynman’s work. Bruce spent the next two years as a research associate at MIT.
Bruce will be most remembered for his major contributions to theoretical nuclear physics. In the 1950s, these were the new—and related—subjects of deuteron stripping (direct reactions) and the nuclear shell model. While at MIT, he took interest, with Marvin Goldberger, in deuteron stripping. In 1950, Bruce joined the Rochester faculty as a Jewett Research Fellow. There, with his first student, Paul Daitch, he developed the theory of stripping as a tool for nuclear structure. Through the decade, Bruce, with his students, developed formalism for calculating nuclear spectra in the interacting shell model, and methods of extracting shell-model information through stripping and similar reactions. He and his student Malcolm Macfarlane wrote the influential 1960 Reviews of Modern Physics article on stripping reactions and the structure of light-to-medium nuclei.
Bruce introduced formalism based on tensorial operators, which incorporated the methods of group theory and second quantization into shell-model theory. (One of his students told me that, to work in this field, one had to learn “French.”) Through these methods, he derived sum rules and particle–hole relations, which he could use to connect seemingly disparate spectroscopic data. Although his style was often formal and “elegant” (one of his favorite words), his goal was to increase the understanding of nuclear structure.
Bruce was instrumental in persuading Harry Gove to come to Rochester to propose a new nuclear accelerator laboratory centered on an MP tandem Van de Graaff and subsequently to direct the lab, which was funded in 1963. Soon after, with former students Edith Halbert of Oak Ridge National Laboratory and Sam Wong of Rochester and the University of Toronto, and with Joe McGrory of Oak Ridge, Bruce was engaged in the development of the Rochester–Oak Ridge shell-model code, one of the early flexible computer codes designed for complex spectroscopy. He felt strongly that such a tool should be accessible to experimentalists for analysis of their own data.
Beginning in about 1970, as shell-model theory and nuclear experiments began to deal with more complex spectra, Bruce’s view of the subject began to change. He recognized that, although spectra in the middle of larger shells increased in complexity, they carried no more information about interactions, orbital structure, and so forth than do much simpler spectra near closed shells. Based on this insight, Bruce, with the help of a number of collaborators and students, developed a statistical approach. He started with the theory of random matrices (of Eugene Wigner, Freeman Dyson, and M. L. Mehta), which he extended to incorporate both interactions and orbital features of the shell model. This is now a subject of its own—statistical spectroscopy—which has been applied to studies of fundamental symmetries (parity and time-reversal invariance) in nuclei, to quantum chaos, and to statistical mechanics of small quantum systems (for example, metallic clusters).
Bruce’s influence on nuclear theory was through his own innovative work and that of his many research students and postdoctoral research associates. He was a frequent visitor to many laboratories and institutes in the US and abroad. Those academic leaves have influenced research at those institutions. Bruce’s published lecture notes from several of the visits and summer schools during the 1960s and 1970s served as textbooks for researchers in the field.
Bruce’s work was centered in Rochester from 1950, when he first arrived, until his retirement in 1992 as the Andrew Carnegie Professor of Physics. Having supervised 23 doctoral students and guided as many postdoctoral fellows, he was heavily involved in the education of graduate students in physics. He and his wife, Helen, were generous hosts to the many visitors to and collaborators with the nuclear theory group.
Bruce was respected for his good judgment in both scientific and general departmental matters. Although he could appear reserved or even aloof, he was generous with his time, open to discussion, and willing to give thoughtful advice. He will be missed by all who knew him.
