2024 Oppenheimer Lecture Featurint Andrea Liu
Monday, April 15, 2024, at 5:30 pm
Chevron Auditorium at International House
A reception was held at 4:30 in the Slusser Room
View photos from the event HERE
Physical systems that can learn by themselves
in 1972 Phil Andersen articulated the motto of condensed matter physics as “More is different.” However, for most condensed matter systems many more is quite similar to more—this is why computer simulations of relatively small systems give insight into far larger systems. There are, however, systems in which many more is different. For example, the capabilities of artificial neural networks grow with their size. Unfortunately, so does the time and energy required to train them. By contrast, brains learn and perform an enormous variety of tasks on their own, using relatively little energy. Brains are able to accomplish this without an external computer because their analog constituent parts (neurons) update their connections without knowing what all the other neurons are doing using local rules. We have developed an approach to learning that shares the property that analog constituent parts update their properties via a local rule, but does not otherwise emulate the brain. Instead, we exploit physics to learn in a far simpler way. Our collaborators have implemented this approach in the lab, developing physical systems that learn and perform machine learning tasks on their own with little energy cost. These systems should open up the opportunity to study how many more is different within a new paradigm for scalable learning.
Andrea Liu
Andrea Liu is a theoretical soft condensed matter physicist. She is best known for developing the field of jamming, which provides a unifying conceptual framework for understanding commonalities in systems ranging from atomic and molecular glasses, to colloidal glasses and granular matter. Liu was born in New York and grew up in Iowa. She received her AB degree in physics at the University of California, Berkeley, and her PhD in the area of critical phenomena from Cornell University in 1989. After switching to complex fluids during her postdoc at Exxon Research and Engineering Co., she worked on polymer theory as a postdoc in the Chemical Engineering, Materials Science and Physics departments at the University of California, Santa Barbara. She then joined the Department of Chemistry and Biochemistry at the University of California, Los Angeles, where she was a member of the physical chemistry faculty for ten years before moving to the Department of Physics and Astronomy at the University of Pennsylvania in 2004, where she is now the Hepburn Professor of Physics.
Research Interests
Andrea Liu’s research combines theory and computation to study soft and living matter. In living matter, her research focuses on the role of mechanics in biology, with the aim of understanding how new and general collective phenomena, often beyond those typically observed in inanimate soft matter, can emerge at the subcellular, cellular and tissue levels. In soft matter, she and her collaborators have shown that jamming produces solids at an opposite pole from perfect crystals, providing a new way of thinking about the nature of rigidity in disordered solids. The nonequilibrium jamming transition and jammed state thus serve as useful starting points for understanding a broad class of materials, including glasses.
Among Dr. Liu's awards are a National Science Foundation CAREER Award, a Simons Investigator in Theoretical Physics, a Simons Fellowship in Theoretical Physics and others. She is a member of the National Academy of Sciences, and a Fellow of the American Association for the Advancement of Science.