Leo Philip Kadanoff was born on January 14, 1937, and died on October 26, 2015.

Leo was an American physicist. He was a professor of physics (emeritus as of 2004) at the University of Chicago and a former President of the American Physical Society (APS).

He contributed to the fields of statistical physics, chaos theory, and theoretical condensed matter physics.

Leo was raised in New York City. He received his undergraduate degree and doctorate in physics from Harvard University.

After a post-doctorate at the Niels Bohr Institute in Copenhagen, Leo joined the physics faculty at the University of Illinois in 1965.

Leo’s early research focused upon superconductivity.

In the late 1960s, he studied the organization of matter in phase transitions.

Leo demonstrated that sudden changes in material properties (such as the magnetization of a magnet or the boiling of a fluid) could be understood in terms of scaling and universality.

With his collaborators, Leo showed how all the experimental data, then available for the changes, called second-order phase transitions, could be understood in terms of these two ideas.

These same ideas have now been extended to apply to a broad range of scientific and engineering problems, and have found numerous and important applications in urban planning, computer science, hydrodynamics, biology, applied mathematics and geophysics.

In recognition of these achievements, Leo won the Buckley Prize of the American Physical Society (1977), the Wolf Prize in Physics (1980), the 1989 Boltzmann Medal of the International Union of Pure and Applied Physics, and the 2006 Lorentz Medal.

Leo Kadanoff passed away at age 78 in October 2015.