Professor Sidney R. Nagel received a Ph.D. in Physics from Princeton University in 1974. Currently, he is the Stein-Freiler Distinguished Service Professor (2001–present) at the University of Chicago, where he is affiliated with the Department of Physics, the James Franck Institute, and the Enrico Fermi Institute. His research interests include jamming, granular materials, singularities in free-surface flows, and splashing. Professor Nagel's Honors are listed below:
- Alfred P. Sloan Research Fellowship (1979)
- Fellow, American Physical Society (1988)
- Fellow, American Association for the Advancement of Science (1993)
- Quantrell Award for Excellence in Undergraduate Teaching (1996)
- Fellow, American Academy of Arts and Sciences (1997)
- Klopsteg Memorial Lecture Award, American Association of Physics Teachers (1998)
- Oliver E. Buckley Prize, American Physical Society (1999)
- Member, National Academy of Sciences (2003)
- Member, American Philosophical Society (2020)
Out-of-equilibrium systems preserve memories of their formation and training history in a variety of ways allowing for an innovative classification of material and dynamics. I will discuss one case where a cyclically sheared suspension of particles or a charge-density-wave solid (or even a walk in the park!) remembers multiple values from a series of training inputs yet forgets all but two of them at long times despite their continued repetition; however, if noise is added all the memories can be encoded indefinitely! When the packing density is increased, so that the particles become jammed, the evolution takes place in a very rugged energy landscape where scores of local energy minima are visited during each applied oscillation. Nevertheless the jammed solid can readily find the periodic orbits. Memory formation in such a system not only sheds light on how glassy ground states are selected and communicate with one another but also shows a form of memory that allows a new probe of the interactions within a material.