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arXiv 1107.2215cond-mat.mes-hall
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绝热过程的拓扑分类

Topological classification of adiabatic processes

Dganit Meidan, Tobias Micklitz, Piet W. Brouwer

摘要:

某些带绝缘体允许量子化电荷或自旋的绝热泵浦,以获得特殊的哈密顿量的时间依赖性。这些“拓扑泵”是密切相关的二维拓扑绝缘相的物质后,滚动的绝缘体到一个圆柱体和线程与时间相关的通量。在这篇文章中,我们将拓扑泵的分类扩展到维格纳戴森和手性类,耦合到多通道引线。根据系统的散射矩阵,给出了区分不同拓扑类的拓扑指数。我们认为,类似于拓扑非平凡的绝缘体,拓扑泵的特点是在泵周期的过程中的保护无隙端态的外观。我们表明,这一性质允许在弱耦合极限的量子化电荷或自旋的泵。我们的结果也可以应用到二维拓扑绝缘体,在那里他们给出了一个物理上透明的解释的拓扑非平凡阶段的散射矩阵。

英文摘要:

Certain band insulators allow for the adiabatic pumping of quantized charge or spin for special time-dependences of the Hamiltonian. These "topological pumps" are closely related to two dimensional topological insulating phases of matter upon rolling the insulator up to a cylinder and threading it with a time dependent flux. In this article we extend the classification of topological pumps to the Wigner Dyson and chiral classes, coupled to multi-channel leads. The topological index distinguishing different topological classes is formulated in terms of the scattering matrix of the system. We argue that similar to topologically non-trivial insulators, topological pumps are characterized by the appearance of protected gapless end states during the course of a pumping cycle. We show that this property allows for the pumping of quantized charge or spin in the weak coupling limit. Our results may also be applied to two dimensional topological insulators, where they give a physically transparent interpretation of the topologically non-trivial phases in terms of scattering matrices.

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