Experimental Period‐n‐Tupling Oscillations in a Photonic Lattice

ABSTRACT The spontaneous breaking of the time translation symmetry has led to the emergence of quantum time crystals as a novel phase of matter, which is a phenomenon sustained by quantum coherence over long periods. Among them, discrete time crystals are recognized by the spontaneous generation of robust subharmonic oscillations. So far, most time crystals are restricted to exhibit a “period‐doubled” behavior. However, a fertile ground in time crystalline with period‐‐tupling has been suggested. Here we experimentally realize scalable period‐2‐tupling and period‐‐tupling in the one‐ (1D) and two‐dimensional (2D) photonic lattices, respectively. In this non‐interacting system, no spontaneous symmetry breaking occurs; instead, the period‐‐tupling arises from the preparation of specific superpositions of eigenmodes with quasienergy gaps of . All levels of the 2D spectrum are paired with different gaps, so that different response periods can be achieved by exciting different sites of the same lattice. The period ‐tupling is robust against perturbations over an extraordinarily long time evolution. The results may promote further research into arbitrary higher‐order time crystals in interacting photonic systems and into non‐equilibrium physics adopting Floquet driving. Next‐generation quantum devices, such as topologically protected quantum state registers, quantum sensors, and simulators, can also be inspired by this approach.