  We investigate the optimal control of open quantum systems, in particular,
the mutual influence of driving and dissipation. A stochastic approach to
open-system control is developed, using a generalized version of Krotov's
iterative algorithm, with no need for Markovian or rotating-wave
approximations. The application to a harmonic degree of freedom reveals
cooperative effects of driving and dissipation that a standard Markovian
treatment cannot capture. Remarkably, control can modify the open-system
dynamics to the point where the entropy change turns negative, thus achieving
cooling of translational motion without any reliance on internal degrees of
freedom.
