Correlation effects in quantum dots and wires

量子点和量子线的相关效应

• 批准号: 35776612
• 负责人: Professor Dr. Volker Meden
• 金额: --
• 依托单位: Institut für Festkörperphysik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/35776612?language=en
• 关键词: Correlation; effects; quantum; dots; wires

In this project we investigate correlation effects in (quasi) one-dimensional quantum wires and in “zero”-dimensional quantum dots with a particular focus on the transport properties of such systems in the linear response regime and singleparticle spectral properties. We have successfully applied a truncation scheme leading to a static self-energy to problems of direct experimental relevance (“phase lapse puzzle” and charging of multi-level dots, Josephson current through correlated quantum dot). The static approximation can only be used in situation in which inelastic processes are irrelevant (e.g. temperatur T = 0 conductance). We thus extended the truncation scheme and kept the frequency dependence of the two-particle vertex which within the one-particle irreducible functional RG leads to a frequency dependent self-energy. We applied this scheme to study the singleimpurity Anderson model (in the appropriate parameter regime dominated by spin fluctuations) and the interacting resonant level model (dominated by charge fluctuations). We discussed the merits and drawbacks of this scheme. We will try to improve on the latter (higher-order corrections). Next we will use the frequency dependent approximation to investigate more complex systems of quantum dots showing a physics which is dominated by the interplay of the Kondo effect and other interactions (such as the RKKY). We will extend the frequency dependent scheme to study quantum wires. An interesting question is the crossover between bulk and boundary Luttinger liquid physics. Finally, we will use the frequency dependent scheme to study fermionic systems coupled to bosons (e.g. local electronic levels coupled to phonons.)

在这个项目中，我们研究了（准）一维量子线和“零”维量子点中的相关效应，特别关注此类系统的传输特性，研究了线性响应范围和单粒子光谱特性。截断方案导致静态自能与直接实验相关的问题（“相移难题”和多级点的充电，通过相关量子点的约瑟夫森电流）静态近似只能用于在非弹性过程不相关的情况下（例如温度 T = 0 电导），我们因此扩展了截断方案并保留了双粒子顶点的频率依赖性，这在单粒子不可约泛函 RG 中导致了频率依赖的自能。我们应用这个方案来研究单杂质安德森模型（在以自旋波动为主的适当参数范围内）和相​​互作用共振能级模型（以电荷波动为主）我们讨论了优点和。我们将尝试改进（高阶校正）。 接下来，我们将使用频率相关近似来研究更复杂的量子点系统，该系统显示出由近藤效应和其他效应的相互作用主导的物理现象。我们将扩展频率相关方案来研究量子线。最后，我们将使用频率相关方案来研究耦合的费米子系统。玻色子（例如与声子耦合的局部电子能级。）