A quantum gas magnifier for an optical quasicrystal*

Ultra-cold atoms in optical lattices are powerful quantum simulators that enable highly tuneable and controllable experiments for studying complex emergent many-body phenomena, particularly in condensed matter physics. In recent years, single-site resolved imaging has emerged as a technique for measuring the real-space atomic distribution in optical lattices.  Quantum gas microscopes are standard tools used in most site-resolved optical lattice experiments. However, they require all sites to be identical and are hence not directly applicable to optical quasicrystals. Alternatively, the recently demonstrated quantum gas magnifier (QGM) utilizing matter-wave optics is a technique that works for both periodic lattices and quasicrystals (QCs).   

In our experiment, we investigate ultra-cold bosons in a two-dimensional 8-fold rotationally symmetric optical QC, offering a versatile platform for tuning quasi-disorder and interaction. It can give rise to novel phases including the Bose glass (BG), which is a localized but compressible quantum state. Enabled by a QGM, we probe the real-space distribution of the QC with single-site resolution across the weakly interacting phase transition from superfluid (SF) to BG, complementing time-of-flight imaging and enabling studies of the microscopic dynamics.