We investigate coherent control of atomic translational motion in an a
pplied off-resonance dipole optical potential. Since spontaneous emiss
ion can be neglected in this regime, the problem is treated as one of
coherent momentum transfer. We consider both adiabatic and nonadiabati
c regimes of cooling in the framework of the Wigner function formalism
. For the adiabatic case, an approximate solution is obtained correspo
nding to the cooling envelope for an arbitrary time dependence of the
external field. The nonadiabatic cooling process is formulated in term
s of optimal control theory in order to define the most favorable regi
me of cooling under imposed constraints on the intensity of the contro
l field. We find that the applied control field yields a significant r
eduction of the effective temperature of the atoms. [S1050-2947(98)018
08-3].