Kadanoff takes Newton Prize

3 July 2011

Professor Leo Kadanoff, a theoretical physicist whose research has spanned a variety of fields, has been awarded the Institute’s Isaac Newton Medal and Prize. The medal is given for outstanding contributions to physics and is the only Institute medal that is open to an international field.

Professor Leo Kadanoff

This is the fourth year in which the medal has been presented, the previous winners being quantum physicist Anton Zeilinger, particle physicist and cosmologist Alan Guth, and theoretical physicist Edward Witten, an expert in superstring theory and supersymmetric quantum field theory.

Kadanoff is an emeritus professor of physics at the University of Chicago and a former president of the American Physical Society. During his career he has worked on areas as diverse as superconductivity, phase transitions, urban growth and planning, and disorder, turbulence and chaos in physical systems.

His citation for the Isaac Newton Medal says that the award is for “inventing conceptual tools that reveal the deep implications of scale invariance on the behaviour of phase transitions and dynamical systems”.

He told the IOP: “Phase transitions was the one area in which I made the most original and deep contributions. I started out working in the quantum mechanics of the interactions between electrons and radiation, and in superconductivity, and that occupied my attention for the first half-dozen years that I was a physicist.

“However, after a time I became aware that there was a substantial problem with what happened near the critical point of phase transitions. There had not been very extensive analysis of Lars Onsager’s solution of the 2-dimensional Ising model, so when I had a period on sabbatical in Cambridge in 1965 I worked on that problem. After nine months in Britain I returned to the University of Illinois and I took that calculation and converted the understanding of what I had done to see what might happen near the phase transition.”

Kadanoff grew up in New York and received his undergraduate degree and PhD from Harvard before undertaking post-doctoral research at the Neils Bohr Institute for Theoretical Studies in Copenhagen. He became an assistant professor of physics at the University of Illinois in 1962, going on to become an associate professor in 1963 then professor at the university in 1965.

He became professor of physics and engineering at Brown University in 1969 and professor of physics at the University of Chicago in 1978, becoming the university’s John D and Catherine T MacArthur Distinguished Service Professor of Physics and Mathematics from 1982–2003. Since 2004 he has been emeritus professor of physics at the University of Chicago. Currently he is working on hydrodynamics and problems in general relativity.

Among his achievements, Kadanoff has with others pioneered the study of scaling or fractal patterns that occur as a dynamical system evolves into chaotic behaviour like that of a turbulent fluid. He and others also showed how to use the concept of fractal measures to address complex scale-invariant patterns like those encountered in turbulence.

He has enjoyed working on very different problems in physics. “I believe the tools of a physicist – particularly a theoretical physicist – are useful in a wide variety of contexts,” he said. “Different fields of physics come and go and problems get solved. If you stick with a problem after it has been solved it’s not much fun for you and not of much use to the world. I try to change the area that I work on once every seven years or so – I try to do different things.”

Kadanoff has won numerous medals and prizes and in 1999 he was one of the recipients of the US’s National Medal of Science, awarded by President Clinton. Asked how he felt about winning the Isaac Newton Medal, he said: “I feel absolutely wonderful about it. It’s a recognition made all the more wonderful by hearing about the great people who received the prize before me”.

The winner of the Newton Medal is invited to give the Newton Lecture, and Kadanoff will give the lecture in London in January 2012.