Theory, codes, and numerical simulation of heat transport in multicomponent systems

Heat transport is a topic that is fundamental in many fields, from materials engineering to planetary models. The calculation of the thermal transport coefficient with the Green-Kubo theory in multicomponent fluids, especially in ab-initio simulations, had a severe data analysis issue that this work solved. In this thesis, we derive the entire theory and data analysis framework for the multicomponent Green-Kubo. Then we show the computer codes we developed, allowing the user to apply the approach previously derived. We believe that in science, replicability and reproducibility are essential requirements. Every new technique must come with an open-source and reliable implementation. In the end, we demonstrate a significant application to superionic ammonia, fundamental to understanding the behavior of icy giant planets like Uranus and Neptune, providing an estimate for the thermal transport coefficient.