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. According to theory, the whole universe consisted of quark-gluon plasma in the first split seconds after the Big Bang. On the earth this cosmic primordial "soup" can be observed in big particle accelerators when, for example, the nuclei of lead atoms are accelerated to nearly the speed of light and smashed into each other, which results in particle showers that are investigated with detectors.

High energy physicists have made these two observations as well when producing quark-gluon plasmas in particle accelerators. The Innsbruck quantum gas experiment can be regarded as a model system to investigate cosmic phenomena that occurred immediately after the Big Bang. "In addition and above all, we can also use this system to address many questions of solid-state physics," says Rudolf Grimm, who is going to further explore the quantum gas mixture with his research group. "The big goal is to produce quantum condensates, such as Bose-Einstein condensates consisting of molecules made up of lithium and potassium atoms. This will tremendously increase our capabilities to realize novel states of matter." The physicists have published their findings in the scientific journal Physical Review Letters.