Collective Phenomena in Random Media

University Of California-Davis, Davis CA

Investigators

Abstract

9985978 Zimanyi This grant continues the NSF support of the collaborative work of two mid-career PI's from UC Davis. Their work, on collective behavior of strongly interacting many-body systems in the presence of disorder, combines analytical and numerical approaches to a variety of problems of current interest. There are 3 related projects: (1) Properties of vortices in high Tc Oxide superconductors, especially those materials where the layering effects are most strongly present. (2) A search will be carried out for a Bose metal phase in disordered superconductors. This project will also involve a study of the interplay between Coulomb interaction and disorder in 2-d metal-insulator transition and explore the role of percolation effects in non-self-averaging systems. Finally project (3) consists of an extensive study of the hysteretic phenomena in recording media. Early results indicate persistence of self-organized criticality in realistic versions of Sherrington-Kirkpatrick models. It may be that in these models, such effects as aging, domain nucleation, domain wall propagation and avalanche formation play an essential role. %%% This grant continues the NSF support of the collaborative work of two mid-career PI's from UC Davis. These PI's work on a variety of problems of current interest, ranging from high Tc superconductors to properties of magnetic recording media. In the former, they are continuing with a detailed exploration of subtle effects of magnetic field on the superconducting properties. They are, in particular interested in the enhancement of these effects in systems which are more layer-like. In the magnetic recording media, they plan to further explore their early results from model calculations which show the presence of "self-organized criticality". ***