Periodically driving a many-body localized quantum system

Periodically driven quantum many-body systems can display rich dynamics and host exotic phases that are absent in their undriven counterparts. However, in the presence of interactions such systems are expected to eventually heat up to a simple infinite-temperature state. One possible exception is a periodically driven many-body localized system, in which heating is precluded by strong disorder. Here, we use a gas of ultracold fermionic potassium atoms in optical lattices to prepare and probe such a driven system and show that it is indeed stable for high enough driving frequency. Moreover, we find a novel regime in which the system is exceedingly stable even at low drive frequencies, a particular feature of our driving scheme. Our experimental findings are well supported by numerical simulations and may provide avenues for engineering novel phases in periodically driven matter.