Noise-stabilized discrete time crystals on digital quantum processors

Understand

Floquet many-body phases such as discrete time crystals (DTCs) are typically fragile to imperfections, and stabilizing them on noisy quantum hardware remains a central challenge in nonequilibrium quantum physics.

• Here, we use IBM Eagle and Heron superconducting processors to implement Floquet dynamics of a kicked Ising model on two-dimensional Kagome lattices, engineered via ancilla-assisted embeddings into the heavy-hex connectivity of the devices.
• By combining error-mitigated measurements on quantum hardware with matrix-product-state simulations incorporating an ancilla-noise model constructed from experimental device data, we observe long-lived subharmonic magnetization oscillations that are stabilized -- rather than destroyed -- by structured quantum noise.
• Across different two-dimensional lattice geometries, increasing cases beyond Kagome lattices, and with or without boundary symmetry-charge pumping, ancilla errors effectively act as spatiotemporal disorder that induces stochastic sign flips of the Ising couplings, providing a unified mechanism for robust period-doubling responses.