ACTIONS
1997INTER ACTIONS
1997
Retirement
Professor Raymond A. Sorensen retired in June from the Carnegie Mellon physics department after an association of 46 years. He joined the department as a junior undergraduate physics major in 1951 after two years at the College of Wooster in Ohio. He received the B.S. degree with the class of 1953 and the Ph.D. in 1958. After a year at the Niels Bohr Institute in Copenhagen and two years at Columbia University in New York, he joined the faculty of our physics department. He continued to the present time doing research and teaching in the department, except for leaves in Copenhagen, Stockholm and Seattle. He was department chairman from 1980-1989.
Sorensen's Ph.D. thesis was done under the direction of G.C. Wick with additional advice from the late Professor Cutkosky. This work involved calculation of electromagnetic effects on the masses of protons, neutrons and pi mesons.
At the time of Sorensen's post-doctoral year the Bohr Institute was directed by Niels Bohr's son Aage and by Ben Mottleson, who jointly won the Nobel prize for work done during that period. The theory of pairing correlations in nuclei, developed in analogy with the superconductivity theory of Bardeen, Cooper and Schrieffer, was the hot topic in Copenhagen. Len Kisslinger, another American visitor at the Bohr Institute, and Sorensen applied those ideas to calculate nuclear energy levels. A subsequent article in Reviews of Modern Physics became one of the most cited articles in that journal's history. Because of contacts made in Copenhagen, Sorensen was subsequently able to recruit Peter Barnes in nuclear experiment and Len Kisslinger in nuclear theory to join the Carnegie Mellon physics department, forming what continues to be a very successful research program.
At Carnegie Mellon, Sorensen worked with a succession of Ph.D. students and postdoctoral associates applying methods of pairing correlations and other collective effects. During a leave in Stockholm at the Atomic Physics Institute, he was present at the discovery and initial study of super-deformed nuclei. These rapidly spinning nuclei are produced in collisions of heavy ions. Sorensen was co-organizer of two international conferences, and associate editor of Nuclear Physics A.
In addition to calculating nuclear phenomena, Sorensen has made serious efforts to make simple explanations of advanced physics. He has published articles in American Journal of Physics (the "physics teachers journal") on topics such as the Magnetic Hyperfine Anomaly and the Lorentz Contraction. With Michel Baranger he wrote an article in the popular journal, Scientific American, about the size and shape of atomic nuclei. Sorensen taught courses at all levels from college freshman to graduate student. One introductory course was the combined Physics-Calculus course taught jointly with the math department. The needed math was delivered "just in time" as needed for physics applications, and the physics was used to help students visualize the mathematics.
Ray's colleagues at Carnegie Mellon wish him and his wife, Audrey, all the best in their retirement.
