"From Little Vibrations to Quantum Excitement: A Story About Phonons" - Madeleine Msall, Josiah Little Professor of Natural Science Inaugural Lecture

In the laboratory, physicists can create giga- and tera-hertz sound, with frequencies that are millions and billions times greater than audible sound. Each step toward higher frequency allows us to measure proportionally smaller structures and to observe beautiful new interactions of sound and matter. At the smallest energy scales, sound is absorbed or emitted as a phonon, a quantum particle that represents a tiny vibration. Phonons are quantized acoustic energy. They play surprising roles in heat transport, electrical resistance, and optical emission and absorption in solids. Phonon behavior also defines the limits of many cutting-edge technologies, from high efficiency opto-electronic and opto-mechanical systems to dark matter detectors and quantum computers. This talk will introduce the science of phonons, their role in both exotic and ordinary material properties, and the challenges of working with the smallest of sounds.

Madeleine Msall is an experimental physicist who studies phonon transport and interactions in crystalline solids. She has worked in research laboratories around the world, most notably Hokkaido University (Japan), the Max Planck Institute for Solid State Physics (Stuttgart, Germany), and the Paul Drude Institute for Solid State Electronics (Berlin, Germany). Her work relies on careful measurements of acoustic energy flow to study the evolution of high energy pulses in materials, to measure the quality of internal interfaces, and to probe the behavior of electrons at the nanoscale. At Bowdoin, she has mentored more than fifty students in experimental and computational research projects in physical acoustics and maintains laboratory infrastructure for student training in low temperature physics, pulsed optics, focused ultrasound, photolithography, and thin film deposition. She earned her BA in physics at Oberlin College and her MS and PhD at the University of Illinois at Urbana-Champaign.