Novel Correlation Effects in Condensed Matter Physics

在凝聚态系统中，存在着大量的相互作用强烈的自由度。然而，许多Pemonena可以在不显著大于原子长度的单一尺度上相互作用的少量自由度的基础上被理解。自洽的单粒子理论可以充分地描述这些现象。相比之下，在许多情况下，不可能从基于几个自由度的理论中猜测系统的定性行为。本提案的目的是审查这些强相互作用系统中的关联效应。特别是，将对量子反铁磁体中的新关联、高温铜酸盐超导体中的磁关联以及新发现的富勒烯分子固体掺碱超导体中的电子关联效应进行理论研究。理论研究将集中在使用传统模型和技术无法理解的各种材料的物理上。这些材料包括铜基高温超导体、磁性材料和新发现的基于新形式的碳的超导材料--巴克明斯特富勒林。将开发新的理论技术来理解这些复杂的系统。

In condensed matter systems there are a large number of degrees of freedom which interact strongly with each other. Many phemonena, however, can be understood on the basis of a small number of degrees of freedom interacting on a single scale not significantly larger than the atomic length scale. A self-consistent one- particle theory can adequately describe these phenomena. In contrast, there are many instances in which it is impossible to guess the qualitative behavior of the system from a theory based on a few degrees of freedom. The aim of the present proposal is to examine correlation effects in these strongly interacting systems. In particular, theoretical research will be conducted on novel correlations in quantum antiferromagnets, on magnetic correlations in high temperature cuprate superconductors, and on electronic correlation effects in newly discovered superconductors made by doping fullerine molecular solids with alkali atoms. %%% The theoretical research will focus on the physics of various materials which cannot be understood using conventional models and techniques. These materials include the copper-based high temperature superconductors, magnetic materials and the newly discovered superconducting materials based on the new form of carbon, Buckminsterfullerine. New theoretical techniques will be developed to understand these complex systems.