Presidential Young Investigator Award

研究计划将包括：（a）准晶生长和 结构 关于是否 在真实的准晶体中观察到的无序是其固有的 或者仅仅是非最优增长的结果 条件 一个特殊的非均衡增长模型出现了 从质和量上再现这种混乱 在衍射实验中观察到。 一个更有定义的 比较将被设计，因为结构产生的 这个模型的特征是 像玻璃杯一样的无序。 这方面的进展可能是 通过使用电子显微镜， 能力比以前。 (b)低温物理学 超出 在60年代的长冈和无尾熊的工作，令人惊讶的是很少 可以理解（甚至是定性地）关于一个洞的运动 在自旋1/2粒子（电子，3He）的晶格中的空位。 例如：（1）单个空穴是否在 一个二分晶格稳定时，一个有限密度的孔， 介绍？ (2)什么形式的磁有序是由一个 三角形（非二分）晶格中的单个空穴？ 这些是 其中最简单的，高度相关的费米子系统， 非平凡的，对它的直观理解是完全 缺乏 通过使用试验波函数和各种 其他计算技术，这些和类似的问题将 追究

The research plan will consist of: (a) Quasicrystal growth and structure. There is still a great deal of controversy whether the disorder observed in real quasicrystals is intrinsic to this phase of matter or just a consequence of non-optimal growth conditions. A particular non-equilibrium model of growth appears to reproduce both qualitatively and quantitatively the disorder observed in diffraction experiments. A more difinitive comparision will be devised since the structures generated by this model very definitely are characterized as having intrinsic disorder, similar to a glass. Progress in this direction may be made by using the electron microscope in a more quantitative capacity than previously. (b) Low temperature physics. Beyond the work of Nagaoka and Thouless in the 60`s, surprisingly little is understood (even qualitatively) about the motion of a hole (vacancy) in a lattice of spin 1/2 particles (electrons, 3He). Examples: (1) Is the ferromagnetism induced by a single hole in a bipartite lattice stable when a finite density of holes is introduced? (2) What form of magnetic ordering is induced by a single hole in a triangular (nonbipartite) lattice? These are among the simplest, highly correlated fermion systems which are nontrivial and for which an intuitive understanding is completely lacking. Through the use of trial wavefunctions and various other computational techniques, these and similar problems will be investigated.