Photoionization-Induced Floquet Driving of a Discrete Time Crystal in a Thermal Rydberg Ensemble

Nonequilibrium, strongly interacting systems exhibit rich dynamics even in the presence of strong dissipation. For example, periodic dynamics, such as discrete time crystalline (DTC) phases, can appear. The DTC phase structure can be further enriched using external periodic driving-Floquet driving. In this Letter, we study a photoionization-induced Floquet driving of a DTC phase in a thermal Rydberg gas. We add an additional laser to induce photoelectrons from the cell wall. These electrons are rotated around the magnetic-field vector and collide with the Rydberg atoms, generating a plasma with large electric fields that perturb further Rydberg excitation. This results in a photoionization-induced Floquet driving of the DTC phase. Importantly, we demonstrate experimentally how the DTC phase relies on the emergence of bistability. Simulations of the mean-field Floquet-driven system reproduce the experimental observations. Our Letter fills an experimental gap in our understanding of the relation of multistability and dissipative discrete time crystals, and in this regard, it constitutes a highly controlled platform for exploring exotic nonequilibrium physics in dissipative interacting systems.