Phasonic control, dynamical localization and extended critical region using Floquet engineering with ultracold strontium gases

We report recent experimental studies of dynamics and localization using ultracold strontium atoms in an 1D bichromatic optical lattice. This system realizes the Aubry-André-Harper model, a prototypical tool for the study of localization, pseudo-disorder, and quasicrystals. Driving the phasonic degree of freedom unique to the quasicrystal, we have demonstrated coherent control of Aubry-André localization. Periodically pulsing the secondary optical lattice realizes the hitherto-unexplored kicked Aubry-André-Harper model. To explore the phase diagram of this model as a function of disorder strength and kick period, we developed a Floquet apodization technique. Applying this technique, we observe signatures of an extended critical regime of multifractal wavefunctions.