论文标题
部分可观测时空混沌系统的无模型预测
Nevanlinna Analytical Continuation
论文作者
论文摘要
有限温度量子系统的仿真提供了假想的频率绿色功能，与实验可测量的实际频谱函数相对应。但是，由于从虚构到真实频率的延续转换不良的条件不良，既定的方法往往会在高频下清洗光谱特征，或者产生具有非物理负零件的光谱函数。在这里，我们表明，明确尊重绿色功能的分析“ nevanlinna”结构会导致内在正面和归一化的光谱函数，并且我们提出了持续的分数扩展，从而产生与分析结构一致的所有可能功能。 Application to synthetic trial data shows that sharp, smooth, and multi-peak data is resolved accurately. Application to the band structure of silicon demonstrates that high energy features are resolved precisely. Continuations in a realistic correlated setup reveal additional features that were previously unresolved.通过实质上增加实际频率计算的分辨率，我们的工作克服了有限温度量子模拟的主要局限性之一。
Simulations of finite temperature quantum systems provide imaginary frequency Green's functions that correspond one-to-one to experimentally measurable real-frequency spectral functions. However, due to the bad conditioning of the continuation transform from imaginary to real frequencies, established methods tend to either wash out spectral features at high frequencies or produce spectral functions with unphysical negative parts. Here, we show that explicitly respecting the analytic `Nevanlinna' structure of the Green's function leads to intrinsically positive and normalized spectral functions, and we present a continued fraction expansion that yields all possible functions consistent with the analytic structure. Application to synthetic trial data shows that sharp, smooth, and multi-peak data is resolved accurately. Application to the band structure of silicon demonstrates that high energy features are resolved precisely. Continuations in a realistic correlated setup reveal additional features that were previously unresolved. By substantially increasing the resolution of real frequency calculations our work overcomes one of the main limitations of finite-temperature quantum simulations.
