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Transport Theoretical Studies of Some Microscopic and Macroscopic Systems.

机译：某些微观和宏观系统的传输理论研究。

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摘要

This dissertation is a report on theoretical transport studies of two systems of vastly different sizes. The first topic is electronic motion in quantum wires. In recent years, it has become possible to fabricate wires that are so small that quantum effects become important. The conduction properties of these wires are quite different than those of macroscopic wires. In this dissertation, we seek to understand scattering effects in quantum wires in a simple way. Some of the existing formalisms for studying transport in quantum wires are reviewed, and one such formalism is applied to calculate conductance in some simple systems. The second topic concerns animals which move in groups, such as flocking birds or schooling fish. Exact analytic calculations of the transport properties of such systems are very difficult because a flock is a system that is far from equilibrium and consists of many interacting particles. We introduce two simplified models of flocking which are amenable to analytic study. The first model consists of a set of overdamped Brownian particles that interact via spring forces. The exact solution for the probability distribution is calculated, and equations of motion for continuous coarse-grained quantities, such as the density, are obtained from the full solution. The second model consists of particles which move in one dimension at constant speed, but which change their directions at random. The flipping rates are constructed in such a way that particles tend to align their directions with each other. The model is solved exactly for one and two particles, the first two moments are obtained, and equations of motion for continuous coarse-grained quantities are written. The model cannot be solved exactly for many particles, but the first and second moments are calculated. Finally, two additional topics are briefly discussed. The first is transport in disordered lattices, and the second is a static magnetic model of flocking.
机译：本文是对两种尺寸差异很大的系统的理论输运研究的报告。第一个主题是量子线中的电子运动。近年来，制造如此小的导线使得量子效应变得重要变得可能。这些导线的导电特性与宏观导线的导电特性完全不同。在本文中，我们试图以一种简单的方式来理解量子线中的散射效应。审查了一些现有的研究量子线传输的形式主义，并在一些简单系统中将这种形式主义应用于计算电导。第二个主题涉及成群移动的动物，例如成群的鸟或学鱼。此类系统的传输特性的精确解析计算非常困难，因为羊群是一个远离平衡的系统，由许多相互作用的粒子组成。我们介绍了两个简化的植绒模型，它们适合进行分析研究。第一个模型由一组通过弹簧力相互作用的过阻尼布朗粒子组成。计算概率分布的精确解，并从完整解中获得连续的粗粒度量（例如密度）的运动方程。第二个模型由以恒定速度一维运动但随机改变方向的粒子组成。翻转速率的构造应使粒子趋于彼此对齐。精确求解一个和两个粒子的模型，获得前两个矩，并写出连续的粗粒度量的运动方程。对于许多粒子，无法精确求解该模型，但会计算出第一矩和第二矩。最后，简要讨论了两个附加主题。第一个是无序晶格中的传输，第二个是植绒的静态磁模型。

著录项

  • 作者

    Astwood, Alden Matthew.;

  • 作者单位

    The University of New Mexico.;

  • 授予单位 The University of New Mexico.;
  • 学科 Physics Quantum.;Biophysics General.;Physics General.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 199 p.
  • 总页数 199
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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