Density Matrix Renormalization Group Studies of Quasi One-Dimensional Systems

9870930怀特这位研究人员计划利用怀特开发的密度矩阵重整化群，研究在一些高温铜酸盐超导体的中子散射实验中观察到的空穴和自旋图案--“条纹”。PI计划对大到16x8的掺杂t-J梯形系统进行大量的“数值实验”，目的是回答这样的问题：一条带沿其长度方向是否有很强的超导配对关联？在什么情况下，条纹会出现在两个维度？在低掺杂时，条纹的自然线空穴密度是多少？Pair在条纹之间建立隧道的难度有多大？配对隧道是否大大增强了配对？条纹是相互吸引还是相互排斥？费米面在条纹态是什么样子的？(1，1)条带稳定吗？PI计划增强DMRG，并开发一种计算动力量的方法。此外，还计划扩展三带Hubbard模型和一维电子-声子耦合系统，目的是将DMRG应用于有机导体。该奖项涉及对材料的电子性质的研究，其中强电子-电子相互作用是重要的。这项工作的重点是高温超导体和相关材料。在这个包含强大的计算组件和算法开发的项目中，将使用和改进由PI开发的方法，该方法有望取得重大进展。

9870930 White This investigator plans to study `stripes' which are patterns of holes and spins observed in neutron scattering experiments in some high temperature cuprate superconductors using the density matrix renormalization group (DMRG) developed by White. The PI plans a large number of "numerical experiments" on doped t-J ladder systems as large as 16x8 that are aimed to answer questions such as: Does a stripe have strong superconducting pairing correlations along its length? At what dopings do stripes appear in two dimensions? At low doping, what is the natural linear hole density of a stripe? How easily do pairs tunnel between stripes? Does pair tunneling greatly enhance pairing? Do stripes attract or repel each other? What does the Fermi surface look like in a striped state? Are (1,1) stripes stable? The PI plans to enhance the DMRG and develop a method for calculating dynamical quantities. Also extensions to three band Hubbard models and one dimensional coupled electron- phonon systems is planned with the aim of applying the DMRG to organic conductors. %%% This award involves research on electronic properties of materials in which strong electron-electron interactions are important. The focus of this effort is on high temperature superconductors and related materials. A method developed by the PI that holds promise for significant advance will be used and refined in this project which contains strong computational components and algorithm development.