Theory of Time-Resolved Optical Conductivity of Superconductors: Comparing Two Methods for Its Evaluation
Theory of Time-Resolved Optical Conductivity of Superconductors: Comparing Two Methods for Its Evaluation
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DOI：
10.3390/condmat4030079
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发表时间：
2019-08
期刊：
影响因子：
1.7
通讯作者：
John P. Revelle;Ankit Kumar;A. Kemper
中科院分区：
文献类型：
--
作者：
John P. Revelle;Ankit Kumar;A. Kemper
时间分辨光导率是一种常用的工具来询问失去平衡的量子材料。从理论上讲，计算这个可观察量是一个复杂的主题，文献中讨论了多种方法。使用非平衡凯尔迪什形式主义和电导率的函数导数方法，我们对应用于泵浦超导体的两种特定的光导率计算方法及其显着特征进行了比较。两种方法的区别在于探针的相对运动和选通时间；探测时间或选通时间保持固定，而另一个则进行扫描。我们发现，这两种方法在泵结束后都会产生相同的时间分辨电导率定性特征。然而，通过保持栅极固定来计算电导率可以消除其他方法固有的伪影。我们提供的软件能够基于第一种方法的数据构建第二种方法。
Time-resolved optical conductivity is an often used tool to interrogate quantum materials driven out of equilibrium. Theoretically calculating this observable is a complex topic with several approaches discussed in the literature. Using a nonequilibrium Keldysh formalism and a functional derivative approach to the conductivity, we present a comparison of two particular approaches to the calculation of the optical conductivity and their distinguishing features, as applied to a pumped superconductor. The two methods are distinguished by the relative motion of the probe and gate times; either the probe or gate time is kept fixed while the other is swept. We find that both the methods result in same qualitative features of the time-resolved conductivity after pump is over. However, calculating the conductivity by keeping the gate fixed removes artifacts inherent to the other method. We provide software that, based on data for the first method, is able to construct the second approach.