We develop theoretical methods in chemistry, (bio-)physics, and materials science, with a focus on approaches derived from quantum mechanics, also enhanced by modern machine learning techniques. Our simulations allow detailed atomistic and realistic insight into complex molecular and materials systems. We investigate a broad range of systems — from functional coordination compounds and biomolecules to liquids, interfaces, and other condensed-phase environments. Our work also supports exploration of challenging processes such as solar light-driven reactions and catalysis for sustainable energy research.