Discrete time quasi-crystals in Rydberg atomic chain

Abstract Discrete time quasi-crystals are non-equilibrium phenomena with quasi-periodic order in time domain, an extension of the discrete time-crystal phase. As a natural platform to explore the non-equilibrium phases, Rydberg atomic arrays have demonstrated the quantum simulation of the discrete-time crystal phase, associated with quantum many-body scar state. However, the existence of discrete time quasi-crystal in this platform has yet to be conceived. Here, we propose a method to generate the discrete time quasi-crystal behavior by coupling two discrete time-crystals, where two external driving frequencies have the maximum incommensurability. Upon the characterization of the phase diagram and the robustness, we explore the entanglement entropy between two subsystems. We find that the emergence of the aperiodic response appears at an appropriate driving frequency, which could be well interpreted by the model with two coupled oscillators. Our method thus offers the possibilities to explore the phases of matters in the quantum simulator.