Collective Phenomena in Random Media

9985978 zimanyi这项拨款继续了美国国家科学基金会对加州大学戴维斯分校两位职业生涯中期PI的合作工作的支持。他们的工作，在存在无序的强相互作用的多体系统的集体行为，结合分析和数值方法的各种当前感兴趣的问题。相关项目有3个：(1)高Tc氧化物超导体中涡旋的性质，特别是那些层状效应最强烈的材料。(2)在无序超导体中寻找玻色金属相。本项目还将研究二维金属-绝缘体跃迁中库仑相互作用与无序之间的相互作用，并探索渗透效应在非自平均系统中的作用。最后项目(3)包括对记录媒体中的滞后现象的广泛研究。早期的结果表明，在谢林顿-柯克帕特里克模型的现实版本中，自组织临界状态持续存在。在这些模型中，老化、畴形核、畴壁扩展和雪崩形成等效应可能起着重要作用。这项拨款继续了美国国家科学基金会对加州大学戴维斯分校两位处于职业生涯中期的PI的合作工作的支持。这些PI的工作涉及各种当前感兴趣的问题，从高Tc超导体到磁记录介质的特性。在前者中，他们正在继续详细探索磁场对超导性能的微妙影响。他们特别感兴趣的是在更像层的系统中增强这些效果。在磁性记录介质中，他们计划进一步探索模型计算的早期结果，这些结果显示了“自组织临界性”的存在

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".***