  We introduce a method for the coherent acceleration of atoms trapped in an
optical lattice, using the well-known model for stimulated Raman adiabatic
passage (STIRAP). Specifically, we show that small harmonic modulations of the
optical lattice amplitude, with frequencies tuned to the eigenvalue spacings of
three "unperturbed" eigenstates, reveals a three-state STIRAP subsystem. We use
this model to realize an experimentally achievable method for transferring
trapped atoms from stationary to motional eigenstates.
