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arXiv 1208.0671cond-mat.str-el
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作为几何相位的扩展系统中的电流响应:应用于变分波函数

Current Response in Extended Systems as a Geometric Phase: Application to Variational Wavefunctions

Balázs Hetényi

摘要:

在变分的背景下研究了电流的线性响应理论。表达式推导出的德鲁德和超流的重量一般变分波函数。德鲁德重量的表达式突出了其计算的困难,因为它取决于实际中通常无法获得的精确能量本征值。虽然德鲁德重量是不是在一个简单的形式,线性电流响应示出的几何相位,或可替代地在总的位置偏移算子的期望值方面是可表达的。几何相位的电流响应的贡献,然后分析了一些常用的投影变分波函数(Baeriswyl,Gutzwiller,和组合)。它表明,这种贡献是独立的投影机本身,是由波函数上的投影机被应用。

英文摘要:

The linear response theory for current is investigated in a variational context. Expressions are derived for the Drude and superfluid weights for general variational wavefunctions. The expression for the Drude weight highlights the difficulty in its calculation since it depends on the exact energy eigenvalues which are usually not available in practice. While the Drude weight is not available in a simple form, the linear current response is shown to be expressible in terms of a geometric phase, or alternatively in terms of the expectation value of the total position shift operator. The contribution of the geometric phase to the current response is then analyzed for some commonly used projected variational wavefunctions (Baeriswyl, Gutzwiller, and combined). It is demonstrated that this contribution is independent of the projectors themselves and is determined by the wavefunctions onto which the projectors are applied.

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