We study the time-dependent dynamics of a Bose-Einstein condensate trapped in
an optical lattice. Modeling the system as a Bose-Hubbard model, we show how
applying a periodic driving field can induce coherent destruction of tunneling.
In the low-frequency regime, we obtain the novel result that the destruction of
tunneling displays extremely sharp peaks when the driving frequency is resonant
with the depth of the trapping potential (``multi-photon resonances''), which
allows the quantum phase transition between the Mott insulator and the
superfluid state to be controlled with high precision. We further show how the
waveform of the field can be chosen to maximize this effect.Comment: Minor changes, this version to be published in Phys. Rev. Let
