Our research group uses scanning probe techniques to study quantum matter. Following a proposal by Feynman, instead of studying real materials, we use a complementary approach: we construct highly controllable model systems by moving single atoms and molecules. This allows us to control parameters that are not easy to control in real materials. Examples include the lattice geometry, coupling of specific orbitals, and the coupling strength. Our results not only provide insight into the behavior of real materials, but also make it possible to go beyond the restrictions imposed by real materials. For in depth information about our work, please see the page with publications.