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arXiv 1303.6468cond-mat.mes-hallgr-qchep-th
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从指数定理导出狄拉克费米子的拓扑有效场论

Topological effective field theories for Dirac fermions from index theorem

Giandomenico Palumbo, Roberto Catenacci, Annalisa Marzuoli

摘要:

狄拉克费米子在高能物理学中扮演着核心角色,但众所周知,它们也以准粒子的形式出现在几个支持拓扑有序的凝聚态系统中。本文给出了一种导出一般背景下无质量狄拉克费米子与矢量场和轴矢量规范场耦合的拓扑有效作用量的一般方法。我们的策略的第一步是标准的(在厄米特的情况下),包括在连接的狄拉克算子的行列式与相应的分析指标通过zeta函数正则化。然后,我们引入一个合适的热核分裂,自然选择行列式的纯拓扑部分(即拓扑有效作用)。这种拓扑有效作用量用规范场表示,使用Atiyah-Singer指数定理计算拓扑项的分析指数。本文的主要新结果是提供了一个一致的推广这种方法的非埃尔米特的情况下,一个定义良好的行列式不存在。支持相对论性费米子的量子系统可以通过相应的拓扑有效场论,根据它们对(外部或涌现的)规范场存在的响应进行拓扑分类。

英文摘要:

Dirac fermions have a central role in high energy physics but it is well known that they emerge also as quasiparticles in several condensed matter systems supporting topological order. We present a general method for deriving the topological effective actions of (3+1) massless Dirac fermions living on general backgrounds and coupled with vector and axial-vector gauge fields. The first step of our strategy is standard (in the Hermitian case) and consists in connecting the determinants of Dirac operators with the corresponding analytical indices through the zeta-function regularization. Then, we introduce a suitable splitting of the heat kernel that naturally selects the purely topological part of the determinant (i.e. the topological effective action). This topological effective action is expressed in terms of gauge fields using the Atiyah-Singer index theorem which computes the analytical index in topological terms. The main new result of this paper is to provide a consistent extension of this method to the non Hermitian case where a well-defined determinant does not exist. Quantum systems supporting relativistic fermions can thus be topologically classified on the basis of their response to the presence of (external or emergent) gauge fields through the corresponding topological effective field theories.

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