Mitchell Feigenbaum

Mitchell Feigenbaum (1944 to 2019) was an American mathematical physicist whose pioneering studies in chaos theory led to the discovery of the Feigenbaum constants. Born in Philadelphia, he studied at the City College of New York and took his doctorate at the Massachusetts Institute of Technology in 1970 with a thesis on dispersion relations. In 1975, working with an HP-65 calculator, he found that the ratio of the gaps between successive period-doubling bifurcations tends to a constant of about 4.6692, and he then showed that the same behavior and constant arise across a wide class of functions before the onset of chaos. This universal result gave mathematicians their first steps into the study of chaotic systems, and in 1986 he shared the Wolf Prize in Physics with Albert Libchaber. He also developed fractal methods for computer cartography for Hammond, and he held the Toyota Professorship at Rockefeller University from 1987 until his death.