In my talk, I will discuss a new technique that uses a time-dependent parabolic potential to slow down a Gaussian wave packet of a particle. This potential that achieves this goal is not unique, but depends on any predetermined classical trajectory of the wave packet’s center-of-mass and the desired time evolution of  its width. As a result, we can not only decelerate a particle exponentially, but also accelerate it. In addition, the ability to choose the time dependence of the wave packet width opens up the possibility of engineering the final quantum state. Finally, I will address several issues that arise: (i) Can this method be generalized to initial wave functions other than Gaussians? (ii) How sensitive is the potential to the parameters of the initial state?