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arXiv 1107.5012cond-mat.mes-hallcond-mat.str-el
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分数量子霍尔效应中的有效场论和隧穿电流

Effective field theory and tunneling currents in the fractional quantum Hall effect

Samuel Bieri, Juerg Froehlich

摘要:

本文综述了“阿贝尔”量子霍尔流体的低能有效场论及其态空间的构造。本文用Chern-Simons理论描述了2+1维带边界流形上不可压缩流体的标度极限。在这样的场论中,规范不变性意味着在样品的边缘上存在反常的手征模。我们假设一个简单的边界结构,即,缺少重建的边缘。对于体积,我们考虑一个多连通的平面几何。我们研究了流体两个边界成分之间的隧穿过程,并计算了隧穿电流作为直流偏置电压的函数的微扰理论的最低阶。特别注意的是支付的特殊情况下,当边缘模式以相同的速度传播,当他们表现出两个显着不同的传播速度。我们区分两个“几何形状”的干涉轮廓对应的(电子)法布里-珀罗和马赫-曾德尔干涉仪,分别。我们发现,当流体中正好有一个孔对应于隧道过程中涉及的两个边缘分量之一时,电流中的干扰项不存在(即,在Mach-Zehnder干涉仪的情况下)。我们分析了隧穿电流对量子霍尔流体的状态和通过样品的外部磁通量的依赖性。

英文摘要:

We review the construction of a low-energy effective field theory and its state space for "abelian" quantum Hall fluids. The scaling limit of the incompressible fluid is described by a Chern-Simons theory in 2+1 dimensions on a manifold with boundary. In such a field theory, gauge invariance implies the presence of anomalous chiral modes localized on the edge of the sample. We assume a simple boundary structure, i.e., the absence of a reconstructed edge. For the bulk, we consider a multiply connected planar geometry. We study tunneling processes between two boundary components of the fluid and calculate the tunneling current to lowest order in perturbation theory as a function of dc bias voltage. Particular attention is paid to the special cases when the edge modes propagate at the same speed, and when they exhibit two significantly distinct propagation speeds. We distinguish between two "geometries" of interference contours corresponding to the (electronic) Fabry-Perot and Mach-Zehnder interferometers, respectively. We find that the interference term in the current is absent when exactly one hole in the fluid corresponding to one of the two edge components involved in the tunneling processes lies inside the interference contour (i.e., in the case of a Mach-Zehnder interferometer). We analyze the dependence of the tunneling current on the state of the quantum Hall fluid and on the external magnetic flux through the sample.

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