Born on 14 January 1937 in New York City, Leo Kadanoff was a theoretical physicist who made significant contributions in a number of fields. He attended Harvard University, where he earned his doctorate in 1960. While working as a postdoc at the Niels Bohr Institute in Copenhagen, he coauthored with Gordon Baym the classic 1962 textbook Quantum Statistical Mechanics. Kadanoff joined the physics department at the University of Illinois at Urbana-Champaign in 1962, then moved to Brown University in 1969, and finally settled at the University of Chicago in 1978. He was a prolific scientist who contributed not only to statistical mechanics but also to chaos theory, multifractality, scaling and collective phenomena, quantum field theory, string theory, turbulence, and even urban planning. Some of his most important work involved critical phenomena and phase transitions, providing fundamental insights into how matter changes from one form to another. For this work, he shared the 1980 Wolf Prize in Physics with Michael Fisher and Kenneth Wilson. Wilson would go on to receive the 1982 Nobel Prize in Physics, an award that some thought Kadanoff should have shared. Nevertheless, Kadanoff received numerous other honors and awards, including the 1977 Oliver E. Buckley Condensed Matter Prize of the American Physical Society, the 1989 Boltzmann Medal of the International Union of Pure and Applied Physics, APS’s 1998 Lars Onsager Prize, the 1999 US National Medal of Science, the 2006 Lorentz Medal, and the 2011 Isaac Newton Medal of the Institute of Physics. He was a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences, the American Association for the Advancement of Science, and APS. Kadanoff also served as president of APS in 2007. He died in 2015 at age 78 from complications after surgery. (Photo credit: AIP Emilio Segrè Visual Archives, Physics Today Collection)
