Theory and numerical simulation of heat transport in multi-component systems

TL;DR

This paper introduces new theoretical concepts and numerical methods to accurately compute thermal conductivity in multi-component fluids, addressing issues of arbitrariness and numerical instability.

Contribution

It proposes a convective invariance principle and multi-variate cepstral analysis to improve the estimation of thermal conductivity from molecular dynamics simulations.

Findings

Reduced noise in thermal conductivity estimates

Effective handling of multi-component systems

Enhanced numerical stability in calculations

Abstract

The thermal conductivity of classical multi-component fluids is seemingly affected by the intrinsic arbitrariness in the definition of the atomic energies and it is ill-conditioned numerically, when evaluated from the Green-Kubo theory of linear response. To cope with these two problems we introduce two new concepts: a convective invariance principle for transport coefficients, in the first case, and multi-variate cepstral analysis, in the second. A combination of these two concepts allows one to substantially reduce the noise affecting the estimate of the thermal conductivity from equilibrium molecular dynamics, even for one-component systems.