Density Matrix Renormalization Group Studies of Quasi One-Dimensional Systems

9870930白色这名研究人员计划研究“条纹”，这是使用白色开发的密度矩阵重整化群（DMRG）在一些高温铜酸盐超导体中子散射实验中观察到的空穴和自旋的图案。 PI计划在掺杂的t-J梯形系统上进行大量的“数值实验”，这些系统大到16 × 8，旨在回答以下问题：一个条带是否沿着它的长度沿着有很强的超导配对关联？在什么样的掺杂下条纹会出现在二维空间中？在低掺杂时，条纹的自然线性空穴密度是多少？ 电子对在条纹之间穿隧有多容易？电子对隧穿能大大增强配对吗？条纹是互相吸引还是互相排斥？条纹态的费米面是什么样的？（1，1）条纹稳定吗？ PI计划增强DMRG并开发一种计算动力学量的方法。为了将DMRG应用于有机导体，还计划扩展到三带Hubbard模型和一维耦合电子-声子系统。 该奖项涉及对材料的电子性质的研究，其中强电子-电子相互作用很重要。 这项工作的重点是高温超导体和相关材料。 PI开发的一种有望取得重大进展的方法将在本项目中使用和改进，其中包含强大的计算组件和算法开发。

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.