Bridging scales in materials simulations - Quantum versus classical simulations

Despite of the great progress of quantum mechanical (QM) simulations over past 40 years there is still the severe problem of the non-linear scaling of such simulations with increasing system size. This holds especially for the Hartree-Fock (HF) and “beyond HF” based methods, but also Kohn-Sham Density Functional Theory (KS-DFT) and related approximate methods, as for example the Density Functional based “tight binding” (DFTB) lacks a proper scaling behavior to study complex material science problems. In addition, there is also the problem of “bridging the scales”. There exists practically no possibility for a continuous transition from QM to a classical “picture”. I.e., it is difficult to perform “coarse grain” simulations from an atomistic to a continuum macroscopic description. On the other hand classical force fields allow more easily to bridge this gap. However, they are based on empirical rules and not from “first principles”. Solutions to this dilemma are discussed, including the question of the need for quantum mechanical simulations.

Zoom: https://dipc-org.zoom.us/j/92268599426

Youtube: https://youtube.com/live/Em7hZBehRrk