Time Crystals from Single-Molecule Magnet Arrays.

Time crystals, a unique nonequilibrium quantum phenomenon with promising applications in current quantum technologies, mark a significant advance in quantum mechanics. Although traditionally studied in atom-cavity and optical lattice systems, pursuing alternative nanoscale platforms for time crystals is crucial. Here we theoretically predict discrete time crystals in a periodically driven molecular magnet array, modeled by a spin-S Heisenberg Hamiltonian with significant quadratic anisotropy, taken with realistic and experimentally relevant physical parameters. Surprisingly, we find that the time crystal response frequency correlates with the energy levels of the individual magnets and is essentially independent of the exchange coupling. The latter is unexpectedly manifested through a pulse-like oscillation in the magnetization envelope, signaling a many-body response. These results show that molecular magnets can be a rich platform for studying time-crystalline behavior and possibly other out-of-equilibrium quantum many-body dynamics.