9523361 Lee The broad subject area of this project is the physics of strong interactions and the effect of random disorder. An example of strong correlation is the physics of the fractional quantum Hall effect, where an electron gas is subject to a high magnetic field so that only the lowest Landau level is partially occupied. A key question is these systems is whether the composite fermions can be described by Fermi liquid theory. The project proposes to continue studying this important system and to explore new experiments which may provide further information on this fascinating new state. The tools being used include many- body perturbation theory, renormalization group analysis, and, at times, numerical analysis. A successful completion of this project will have significant impact on a broad area of condensed matter physics, including other strongly correlated materals, such as high temperature superconductors and heavy fermion metals. %%% This project theoretically investigates systems of electrons where their repulsion plays a crucial role in determining their physical properties, and the effects of random disorder on such systems. An example that constitutes an important focus is the physics of the fractional quantum Hall effect, in which a magnetic field is applied to a gas of electrons that forms at an interface in semiconductors. The investigator is a distinguished leader in this area of condensed-matter physics, using state-of-the art methods. A successful completion of this project will have significant impact on a broad area of condensed matter physics, including other strongly correlated materals, such as high temperature superconductors and heavy fermion metals. ***