Observation of a prethermal discrete time crystal: a nonequilibrium phase of matter on a quantum simulator*

Quantum simulators, such as chains of trapped ions with engineered spin-spin interactions, have proven to be a powerful platform for the investigation of non-equilibrium physics. For example, periodic driving can result in the creation of novel phases of matter, such as the discrete time crystal, with no static counterpart. However, stabilizing these phases requires preventing runaway heating due to the drive. We demonstrate a technique to evade this heating and realize a prethermal discrete time crystal on a trapped-ion quantum simulator. By applying a high-frequency drive, heating is suppressed, leading to an expansive time window in which nonequilibrium phases can emerge. Our results establish Floquet prethermalization as a general strategy for creating, stabilizing, and studying intrinsically out-of-equilibrium phases of matter.