Graduate Research Programs

CHEMICAL PHYSICS
Professor Pollack's work is aimed at understanding simple gases and liquids from molecular first principles. The main properties measured are solubilities of gases in liquids and diffusion of gas molecules through liquids at different pressures and temperatures. These are determined by molecular properties, thermodynamics and statistical mechanics of solutions, molecular dynamics, and other techniques at the inferface between physics and chemistry. A series of such experiments is done in which one judiciously choses the gases and liquids so that their molecular properties change in a controlled way. One then studies how the observable macroscopic properties change and correlates these changes with the microscopic properties. The work has application to several interesting problems in biological systems including artifical blood.

ACOUSTICS
Professor W. Hartmann The goal of the psychoacoustics program is to understand the way in which the human brain performs elementary perceptual functions, particularly the perception of sound. Mathematical models are constructed based upon the disciplines of signal processing engineering, neurophysiology, and complex systems theory. The models are tested against experiments on human listeners using precisely-controlled stimuli and the protocols of experimental psychology.
There are two topics of primary interest, the localization of sound and pitch perception. Localization experiments in rooms study the way the auditory system copes with interference of reflected waves. Experiments with sources in the median sagittal plane show how the system extracts localization information from a sound field when there are no interaural signal differences. Pitch perception modeling and experiments concern the neural integration of spectral components to create a single perceptual entity or, alternatively, the segregation of distinct different sources from a composite sound field.