9707701 Millis This award is for theoretical research on non-fermi-liquid metals. The main focus of the work will be on the theory of electrons interacting via singular interactions caused by proximity to critical points and for systematic comparisons of the results to experimental data. For the past forty years the central concept on which metal physics is based has been Landau's Fermi Liquid Theory, which holds that at temperatures or energies much less than the Fermi energy, the physics of metallic interacting electrons is isomorphic to the physics of non-interacting electrons. One of the key experimental achievements of the past decade has been the demonstration that many classes of materials (including the high temperature superconductors, many heavy fermion materials and several transition metal compounds) exhibit low temperature behavior which is metallic yet is inconsistent with Fermi Liquid Theory. The physics of these non-fermi-liquid metals is not at all understood. This grant will study this important problem based on the controversial assumption that non-fermi-liquid behavior in metals is somehow related to critical point fluctuations as might be observed in an equilibrium phase transition. %%% This theoretical award will study the properties of metals which are not explained by the theoretical foundation established many years ago. Many materials of current interest, such as the high temperature superconductors, exhibit metallic behavior which cannot be explained by present theory. Consequently, new physical foundations need to be established. Successful completion of this project will have wide impact on the way we interpret the behavior of metals and other materials. ***
