光吸收法测量固体中相互作用修饰的Berry曲率和量子度规
Measurement of interaction-dressed Berry curvature and quantum metric in solids by optical absorption
摘要：
Bloch态在动量空间中的量子几何性质通常用Berry曲率和量子度规来描述。在实际的带隙材料中，相互作用和无序使得Bloch态不是一个可行的起始点，我们通过引入有限温度下的Dressed Berry曲率和量子度规来推广这些概念，其中可以微扰地包括多体相互作用的影响。这些量是从线或圆极化电场引起的电荷极化磁化率中提取的，其光谱函数可以从动量分辨激子或红外吸收率中测量。作为一个具体的例子，我们研究了杂质散射下的Chern绝缘体，结果表明能隙对多体相互作用的量子几何性质具有保护作用.
英文摘要：
The quantum geometric properties of a Bloch state in momentum space are usually described by the Berry curvature and quantum metric. In realistic gapped materials where interactions and disorder render the Bloch state not a viable starting point, we generalize these concepts by introducing dressed Berry curvature and quantum metric at finite temperature, in which the effect of many-body interactions can be included perturbatively. These quantities are extracted from the charge polarization susceptibility caused by linearly or circularly polarized electric fields, whose spectral functions can be measured from momentum-resolved exciton or infrared absorption rate. As a concrete example, we investigate Chern insulators in the presence of impurity scattering, whose results suggest that the quantum geometric properties are protected by the energy gap against many-body interactions.
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