9316587 Ingersent This proposal concerns the physics arising out of interactions between magnetic impurities embedded in non-magnetic materials. Specifically, the behavior of multi-band Kondo and Anderson models are to be studied. Marginal-Fermi-liquid behavior (a suggestion for the normal state of the high Tc materials) is observed for multi- band Kondo and Anderson models, but recent numerical renormalization-group calculations show that when interaction is allowed between impurities, Fermi-liquid behavior is recovered. The PI proposes to expand this work to more complex and/or realistic models and to frustrated magnetic systems coupled to multiple bands. %%% This work concerns elucidation of the behavior of models which have been put forward to describe the electronic properties of materials containing heavy magnetic elements such as the recently discovered high temperature superconductors. Discussion here has revolved around what is the appropriate zeroth order description of the electronic states of such materials. Some of the putative models, at their simplest give certain types of unusual behaviors but the PI has shown that as these models are made more "realistic", then behavior tends to revert to the more usual descriptions with which traditional solid state physics is more familiar. The PI will continue this work towards ever more realistic descriptions. ***
