  We investigate the competition between superconductivity (SC) and charge
density wave (CDW) under a time-dependent periodic field in the attractive
Hubbard model. By employing the time-dependent exact diagonalization method, we
show that the driving frequency and amplitude of the external field can control
the enhancement of either the superconducting pair or the CDW correlations,
which are degenerate in the ground state of the half-filled attractive Hubbard
model in the absence of the field. In the strong-coupling limit of the
attractive Hubbard interaction, the controllability is characterized by the
anisotropic interaction of the effective model. The anisotropy is induced by
the external field and lifts the degeneracy of SC and CDW. We find that the
enhancement or suppression of the superconducting pair and CDW correlations in
the periodically-driven attractive Hubbard model can be well interpreted by the
quench dynamics of the effective model derived in the strong-coupling limit.
