  Controlling non-equilibrium quantum dynamics in many-body systems is an
outstanding challenge as interactions typically lead to thermalization and a
chaotic spreading throughout Hilbert space. We experimentally investigate
non-equilibrium dynamics following rapid quenches in a many-body system
composed of 3 to 200 strongly interacting qubits in one and two spatial
dimensions. Using a programmable quantum simulator based on Rydberg atom
arrays, we probe coherent revivals corresponding to quantum many-body scars.
Remarkably, we discover that scar revivals can be stabilized by periodic
driving, which generates a robust subharmonic response akin to discrete
time-crystalline order. We map Hilbert space dynamics, geometry dependence,
phase diagrams, and system-size dependence of this emergent phenomenon,
demonstrating novel ways to steer entanglement dynamics in many-body systems
and enabling potential applications in quantum information science.
