Abstract

In this work, we elaborate on two recently discovered invariance principles, according to which transport coefficients are, to a large extent, independent of the microscopic definition of the densities and currents of the conserved quantities being transported (energy, momentum, mass, charge). The first such principle, gauge invariance, allows one to define a quantum adiabatic energy current from density-functional theory, from which the heat conductivity can be uniquely defined and computed using equilibrium ab initio molecular dynamics. When combined with a novel topological definition of atomic oxidation states, gauge invariance also sheds new light onto the mechanisms of charge transport in ionic conductors. The second principle, convective invariance, allows one to extend the analysis to multi-component systems. These invariance principles can be combined with new spectral analysis methods for the current time series to be fed into the Green–Kubo formula to obtain accurate estimates of transport coefficients from relatively short molecular dynamics simulations.

Graphic abstract

中文翻译：

---

输运系数理论和计算中的不变性原理

摘要

在这项工作中，我们详细阐述了两个最近发现的不变性原理，根据这些原理，传输系数在很大程度上独立于被传输的守恒量（能量、动量、质量、电荷）的密度和电流的微观定义. 第一个这样的原理，规范不变性，允许人们从密度泛函理论定义量子绝热能量流，从中可以使用平衡从头算分子动力学唯一地定义和计算热导率。当与原子氧化态的新拓扑定义相结合时，规范不变性也为离子导体中的电荷传输机制提供了新的思路。第二个原理，对流不变性，允许将分析扩展到多组分系统。这些不变性原理可以与当前时间序列的新光谱分析方法相结合，以将其输入 Green-Kubo 公式，以从相对较短的分子动力学模拟中获得传输系数的准确估计。

图形摘要