During the action the research fellow has investigated various aspect of Rydberg dressing scheme in many-body systems and non-equilibrium quantum phenomena in a disordered system. The Rydberg dressing technique is essential in realizing a supersolid phase, and the fellow successfully demonstrates this experimental scheme in many-body systems. Furthermore, coherence in the dressed system is recently observed by collapse and revival dynamics. In the experiment, however, the researcher find out the lifetime of the system is significantly shorter than theoretical predictions, which could be attributed to a complex molecular spectrum in dressed system. After finding suitable parameter window that shows enough lifetime, experimental efforts towards the supersolid phase will be continued. Still, the experimental works provide a stepping stone to realize long-range interacting many-body system with Rydberg atoms.
Furthermore, the fellow has observed a many-body localized phase in two-dimensional Bose gas. The many-body localization (MBL) is a new quantum phase in non-equilibrium state, where initial state memory persists for infinitely long time. The major findings in the experiments are as follows. followings are the main questions that we addressed in the experiments. 1) The observation MBL phase transition in two-dimensions 2) Evidence of diverging length scale near the critical disorder. Our findings show the many-body localization is not a theoretical artifact from numerical errors or finite size effect, but it exists in real system. Especially, we have studied the localized phase in two dimensions, where it is impossible to study with the current state-of-art numerical techniques. Thus, our results provide a guide to the development of MBL theory or new tools for simulating complex quantum dynamics.
