Physics Colloquium - Stability and Instability in Soft Matter Physics

Stability and instability in soft matter physics: from neutron star crusts to the central nervous system and beyond

Dr. Tyler Engstrom
Visiting Assistant Professor of Physics
Hobart & William Smith Colleges

Abstract:
When Richard Feynman famously said, “all things are made of atoms,” he wasn’t thinking of neutron star crusts and white dwarf interiors, which are too dense for atoms to exist. But it is this very property makes them resemble certain kinds of soft matter (dusty plasmas and charged colloidal suspensions), only zoomed out about a billion times. In the first part of my talk, I'll show how this resemblance was used in combination with a genetic algorithm to predict new stable crystalline phases of the stellar matter. Implications of these new phases in astrophysical phenomena will be discussed. The second part of my talk will focus on how living tissues take shape as they grow, a process known as morphogenesis. Conventional models of morphogenesis assume that tissue growth (via cell division) is analogous to thermal expansion of elastic solids, and triggers an elastic wrinkling instability. My interdisciplinary team of physicists, biologists, and an engineer used a combination of theory, experiments, and finite element simulations to show that this assumption doesn’t always hold, and we went on to create a new kind of model for morphogenesis within the central nervous system. Our model reveals deep connections between the biology and physics of brain folding. It may also apply to the changing shapes of some fast-growing cities.

Speaker Bio:
Tyler Engstrom earned his B.S. in Materials and Metallurgical Engineering from South Dakota School of Mines & Technology, and his Ph.D. in Physics from Penn State. As a postdoc at Syracuse University, he specialized in theoretical soft matter and biophysics. Most recently, he has been a Visiting Assistant Professor of Physics at Hobart and William Smith Colleges. Tyler lives in Trumansburg, NY, where he owns a woodworking business and tends to several honey bee hives.

Intended Audience:
All are welcome.