Broadened coherent destruction of tunneling

This paper investigates the manipulation of coherent quantum tunneling by controlling second-order coupling in zigzag-shaped lattice arrays with only one site periodically driven against the others. Different from normal coherent destruction of tunneling (CDT), we propose a surprisingly large and nontrivial effect of second-order coupling on broadened CDT essentially attributed to avoided level crossings and localized Floquet states. Moreover, our results at high-frequency approximation supported by exact numerical ones demonstrate that the extent to which the normal CDT is broadened depends on the separation of quasienergy levels in the vicinity of zeros of ${J}_{0}(A/\ensuremath{\omega})$. Remarkably, beyond the intensity of second-order coupling, the lattice size and its parity also significantly influence Floquet dynamics by either facilitating or suppressing tunneling probabilities, which in essence are also determined by noncrossing quasienergies and localized Floquet states. These findings substantially extend the theory of normal CDT, unveil the intrinsic physics behind broadened CDT, and open up an exciting possibility for quantum state control.