Tailoring quantum correlations in mesoscopic systems

How do many body quantum correlations emerge as the size of a system is increased? This depends strongly on the strength of interactions and the dimensionality. In our systems distilled from ultracold atoms, we can tune all major parameters within the limit of contact interactions. Starting the journey from the paradigmatic situation of the BCS superconductor [1], where the Fermi energy is the dominant energy scale, the crossover to the BEC limit of molecular pairing, where the binding energy of the molecules overcomes the Fermi energy has been studied in detail over the past twenty years. Working with a mesoscopic sample the effects of breaking the translational symmetry become important. Thus, the shell structure and a competition between intershell and intrashell pairing, becomes important [2]. Discussed for decades in the context of nuclear physics, we can now directly address this concept by measuring microscopic quantities, such as momentum or position, and spin of all atoms. Going beyond studying the ground state of such systems, we have started to study topological excitations of such systems by introducing angular momentum in a controlled way, mimicking the effects of a large external magnetic field on charged particles with our rotating neutral atoms. As a first step, we engineered a Laughlin wave function created from two atoms [3]. We will present our progress in scaling the atom number to larger rotating systems.