Ultracold bosons in a two-dimensional optical quasicrystal*

The interplay between disorder and interaction is crucial to understanding complex many-body systems. It can lead to the emergence of exotic phases and phenomena in condensed-matter systems that are difficult to engineer and control. Ultra-cold atoms in optical quasicrystals (QC) offer a versatile platform for tuning disorder and interaction to study many-body problems that cannot be probed in conventional periodic systems. They can give rise to novel phases including the Bose glass (BG), which is a localized but compressible quantum state. In our experiment, we realized ultra-cold bosons in a two-dimensional eight-fold optical QC. The weak interacting and strong interacting phase diagrams are measured, demonstrating superfluid (SF), Bose Glass (BG) and Mott insulator phases. The dynamics in QC is probed, including the quenches between SF and BG regimes and the transport properties at different quasi-disorder and interaction strength. A quantum gas magnifier is employed to investigate the system with single-site resolution, enabling the studies of the microscopic dynamics.