Parametric instabilities in a 2D periodically-driven bosonic system: Beyond the weakly-interacting regime

Understand

We experimentally investigate the effects of parametric instabilities on the short-time heating process of periodically-driven bosons in 2D optical lattices with a continuous transverse (tube) degree of freedom.

• We analyze three types of periodic drives: (i) linear along the x-lattice direction only, (ii) linear along the lattice diagonal, and (iii) circular in the lattice plane.
• In all cases, we demonstrate that the BEC decay is dominated by the emergence of unstable Bogoliubov modes, rather than scattering in higher Floquet bands, in agreement with recent theoretical predictions.
• The observed BEC depletion rates are much higher when shaking both along x and y directions, as opposed to only x or only y.