David Weld
The kicked rotor is a paradigmatic model of chaos in driven systems: dynamical localization and a consequent failure to thermalize in the quantum kicked rotor contrasts sharply with classically-expected ergodicity. Despite a quarter-century of atom-optical experimental studies, the effect of interactions on the dynamically localized state has remained unexplored. I will discuss the recent experimental realization of a many-body kicked quantum rotor with Feshbach-tunable interparticle interactions, using a degenerate gas of bosonic lithium in a pulsed optical lattice. As interactions are increased from zero, we observe the emergence of many-body dynamical delocalization and a subdiffusive approach to infinite temperature. Time permitting, I will also discuss recent experimental results on a spiritual relative of the kicked rotor: the kicked Aubry-André-Harper model, in which time-dependent quasiperiodicity can either drive a localization transition or give rise to rapid heating.