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Quantum transport in quantum-chaotic systems

量子混沌系统中的量子传输

基本信息

批准号：
13640391
负责人：
NAKAMURA Katsuhiro
金额：
$ 2.18万
依托单位：
Osaka City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

□Quantum transport and quantum chaos in mesoscopic systems :In the systems showing chaos classically, various interesting problems appear if we apply quantum mechanics to such systems. This gives rise to a birth of the subject of "quantum chaos."Using mesoscopic or nanoscale electronic devices, we can capture "quantum chaos," namely quantum manifestations of classical chaos. For a long time, people have studied stadium and Sinai billiards as typical examples of dynamical system showing chaos and ergodicity. Such billiards whose size are of nanoscale are now being made at the interface of semiconductor heterojunctions, and experiments on ballistic quantum transport in these quantum dots is in progress. We have applied the periodic orbit theory to quantum transport in classically-chaotic quantum dots and succeeded to explain the fractal conductance fluctuations observed in many experiments.□Pattern formation and chaos in nonequilibrium ferromagnets and Bose-Einstein condensations :We are also trying to understand mechanisms underlying the morphological nonequilibrium phase transitions. For instance, we study pattern formations in magnetic thin films in the presence of time-periodic magnetic field by using the fundamental equation (Landau-Lifshitz equation). Since such a study has a quite general and universal feature, we also analyze dynamics of vortices or textures in various Bose-Einstein condensations, too. We have succeeded to explore the effect of nonlinearity on quantum interference and dynamical tunneling in BEC.

□介观系统中的量子输运和量子混沌：在经典的混沌系统中，如果我们将量子力学应用于这样的系统，就会出现各种有趣的问题。这就产生了“量子混沌”这一学科。使用介观或纳米级电子器件，我们可以捕获“量子混沌”，即经典混沌的量子表现。长期以来，人们把体育场和西奈台球作为动力系统表现出混沌和遍历性的典型例子来研究。这种尺寸为纳米级的台球现在正在半导体异质结的界面上制作，并且这些量子点中的弹道量子输运实验正在进行中。我们将周期轨道理论应用于经典混沌量子点的量子输运，成功地解释了许多实验中观察到的分形电导涨落。□非平衡铁磁体和玻色-爱因斯坦凝聚中的图案形成和混沌：我们还试图理解形态学非平衡相变的机制。例如，我们研究图案形成的磁性薄膜中的时间周期磁场的存在下，通过使用的基本方程（朗道-Lifshitz方程）。由于这种研究具有相当普遍的特点，我们也分析了各种玻色-爱因斯坦凝聚中的涡旋或纹理的动力学。我们成功地研究了非线性效应对BEC量子干涉和动力学隧穿的影响。