When many particles interact, they can form collective states of matter, the most common of which are the solid, liquid and gaseous state. The present project will search for new states of matter at ultralow temperatures, using gases of atoms with freely tunable interactions as the starting point. At these low temperatures, quantum mechanics takes center stage, and the intrinsic uncertainty in where each particle is – the Heisenberg uncertainty – strongly affects the behavior of the collection of particles. They commonly form a quantum liquid, but they may enter a superfluid state, where atoms flow without any friction. Understanding such superfluid states is crucial for the understanding of yet another “super” state, namely superconductors, which carry electricity without any heat. The atoms in the experiment will be imaged with single-atom resolution, enabling an unprecedented view into the microscopic origins of various phases of matter. In particular, the research aims to find evidence for a state that is at the same time a superfluid and a solid. These experiments will enhance our understanding of collective phenomena and states of matter. The work will provide excellent training for graduate and undergraduate students on lasers and optics, computer control, vacuum assemblies, high magnetic fields, radiofrequency and microwave electronics, thereby combining research with education objectives. The PI and the team will use ultracold sodium and lithium atoms trapped in t