Collective Phenomena in Random Media

9985978齐马尼这笔赠款延续了NSF对加州大学戴维斯分校两名职业生涯中期PI的合作工作的支持。他们的工作是关于在无序存在时强相互作用的多体系统的集体行为，结合了对当前感兴趣的各种问题的分析和数值方法。与此相关的研究项目有三个：(1)高T_c氧化物超导体的涡旋特性，特别是层状效应最强的材料。(2)寻找无序超导体中的玻色金属相。该项目还将研究二维金属-绝缘体转变中库仑相互作用和无序之间的相互作用，并探索渗流效应在非自平均系统中的作用。最后，项目(3)对记录媒体中的滞后现象进行了广泛的研究。早期的结果表明，在现实版本的Sherrington-Kirkpatrick模型中，自组织临界性持续存在。可能在这些模型中，老化、磁区成核、磁区壁传播和雪崩形成等效应起着至关重要的作用。%这笔赠款延续了美国国家科学基金会对加州大学戴维斯分校两名职业生涯中期PI的合作工作的支持。这些PI在各种当前感兴趣的问题上所做的工作，从高T_c超导体到磁记录介质的性质。在前者中，他们继续详细地探索磁场对超导性质的微妙影响。他们特别感兴趣的是在更具层状的系统中增强这些效应。在磁记录介质中，他们计划进一步探索他们从模型计算中获得的早期结果，这些计算表明存在“自组织临界性”。

9985978ZimanyiThis 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".***