ABSTRACT Theoretical analysis typically involves imaginary-time correlation functions. Inferring real-time dynamical response functions from this information is notoriously difficult. However, as we articulate here, it is straightforward to compute imaginary-time correlators from the measured frequency dependence of (real-time) response functions. In addition to facilitating comparison between theory and experiment, the proposed approach can be useful in extracting certain aspects of the (long-time relaxational) dynamics from a complex data set. We illustrate this with an analysis of the nematic response inferred from Raman scattering spectroscopy on the iron-based superconductor , which includes a new method for identifying a putative quantum-critical contribution to that response.

中文翻译：

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测量量子材料的虚时间动力学

摘要 理论分析通常涉及虚时间相关函数。从这些信息推断实时动态响应函数是非常困难的。然而，正如我们在此阐明的那样，根据（实时）响应函数的测量频率相关性计算虚时间相关器是很简单的。除了促进理论与实验之间的比较外，所提出的方法还可用于从复杂数据集中提取（长期松弛）动力学的某些方面。我们通过分析从铁基超导体的拉曼散射光谱推断出的向列响应来说明这一点，其中包括一种新方法，用于识别对该响应的假定量子临界贡献。