Coherence phenomena have made an impact on society, for instance, via lasers that enable global communication networks. Macroscopic quantum coherence is still, however, a phenomenon that poses open scientific questions. Is it possible to create superconductors that work at room temperature? What are the ultimate limits of energy thresholds needed for lasing, if we utilize the
strong light-matter interactions possible at the nanoscale? Here, we take a new approach to these questions by exploring lattices with non-trivial topological or geometric properties. We aim to discover fundamental bounds to superfluidity and superconductivity: the results can provide the route to room-temperature superconductivity. By combining experiment and theory within our group, we furthermore aim to achieve novel coherent light-sources with low energy consumption and nanoscale operation by using plasmonic nanoparticle arrays with designed geometries.