Quantum Physicists Investigate New States of Matter in Ultracold Atom Mixtures

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 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. Now the group of quantum physicists led by Prof. Rudolf Grimm and PhD Florian Schreck from the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences together with Italian and Australian researchers has for the first time achieved strong controlled interactions between clouds of lithium-6 and potassium-40 atoms. Hence, they have established a model system that behaves in a similar way as the quark-gluon plasma, whose energy scale has a twenty times higher order of magnitude.