Self-Spinning Crystallized Rotating Bose-Einstein Condensates*

The dynamics of interacting Bose-Einstein Condensates (BEC) coupled to artificial gauge fields remains a crucial question for understanding exotic quantum phenomenon like the quantum Hall effect and type-II superconductivity. Under extreme rotation and weak interactions, a Landau gauge BEC will spontaneously crystallize into a persistent array of droplets, due to the balance between effective magnetic forces and interactions¹. Here we study the long-time dynamics of these condensed droplets. We find that in the rotating frame the droplets are spinning at a constant frequency. In Lowest Landau Level (LLL), the rate of rotation continously increases from zero upon turning on interaction. While in Thomas-Fermi regime, when multiple Landau levels are occupied, the rotation speed saturates to a particular fraction of cyclotron frequency. Our results provide a novel realization of time crystals and flat-band localization.

¹Mukherjee, B., Shaffer, A., Patel, P.B. et al. Crystallization of bosonic quantum Hall states in a rotating quantum gas. Nature 601, 58–62 (2022).