Unraveling the dynamical behaviors in a quasiperiodic mosaic lattice

Quasiperiodic mosaic systems have attracted significant attention due to their unique spectral properties with exactly known mobility edges, which do not vanish even in the large quasiperiodic potential strength region, although the width of energy window of extended states becomes very narrow and decreases with the increase of strength of the quasiperiodic potential.In this work we study the dynamics of a quasiperiodic mosaic lattice and unravel its peculiar dynamical properties. By scrutinizing the expansion dynamics of wave packet and the evolution of density distribution, we unveil that the long-time density distribution display obviously different behaviors at odd and even sites in the large quasiperiodic potential strength region. Particularly, the time scale of dynamics exhibits an inverse relationship with the quasiperiodic potential strength. To understand these behaviors, we derive an effective Hamiltonian in the large quasiperiodic potential strength region, which is composed of decoupled Hamiltonians defined on the odd and even sites, respectively. While all eigenstates of the effective Hamiltonian defined on even sites are localized, the eigenstates of effective Hamiltonian defined on odd sites include both localized and extended eigenstates. Our results demonstrate that the effective Hamiltonian can describe the dynamical behaviors well in the large quasiperiodic potential strength region and provides an intuitive framework for understanding the peculiar dynamical behaviors in the quasiperiodic mosaic lattice.
Comment: 11 pages, 7 figures