Description:

The Physics of Active Matter

Birds flock, bees swarm and fish school. These are just some of the remarkable examples of collective behavior found in nature. Physicists have been able to capture some of this behavior by modeling organisms as ``flying spins’’ that align with their neighbors according to simple but noisy rules. Successes like these have spawned a field devoted to the physics of active matter – matter made not of atom and molecules but of entities that consume energy to generate their own motion and forces. Through interactions, collectives of such active particles organize in  emergent structures on scales much larger than that of the individuals. There are  many examples of this spontaneous organization in both the living and non-living worlds:  motor proteins orchestrate the organization of genetic material inside  cells,  swarming bacteria self-organize into biofilms, epithelial cells  migrate collectively to fill in wounds,  engineered microswimmers self-assemble to form smart materials. In this lecture I will introduce the field of active matter and highlight ongoing efforts by physicists, biologists, engineers and mathematicians to model the complex behavior of these systems, with the goal of  identifying universal principles. 

Biographical Information

M. Cristina Marchetti is a Distinguished Professor of Physics at the University of California Santa Barbara. She was educated in Italy at the University of Pavia, earned her Ph.D. in the U.S. at the University of Florida, and joined the faculty at UC Santa Barbara in 2018, after thirty years on the faculty at Syracuse University.  Marchetti is a theoretical physicist who has worked on a broad range of problems in condensed matter physics, including supercooled fluids, superconductors and driven disordered systems. Currently, she is interested in understanding the emergent behavior of active matter. The name refers to large collections of self-driven agents that exhibit organized behaviors on scales much larger than that of the individuals. Examples range from the flocking of birds to the sorting and organization of cells in morphogenesis, and include synthetic analogues, such as active colloids and engineered microswimmers. Marchetti is currently co-lead editor of the Annual Reviews of Condensed Matter Physics.  She is a Fellow of the American Physical Society and of the American Association for the Advancement of Science, and a member of the American Academy of Arts and Sciences and of the US National Academy of Sciences. In 2019 she was awarded the inaugural Leo P. Kadanoff prize by the American Physical Society.