Scientists of the Institute for Quantum Optics and Quantum Information (IQOQI) in Innsbruck, Austria, have reached a milestone in the exploration of quantum gas mixtures. In an international first, the research group led by Rudolf Grimm and Florian Schreck has succeeded in producing controlled strong interactions between two fermionic elements — lithium-6 and potassium-40. This model system not only promises to provide new insights into solid-state physics but also shows intriguing analogies to the primordial substance right after the Big Bang.