DISPERSION-FREE WAVE-PACKETS AND FEEDBACK SOLITONIC MOTION IN CONTROLLED QUANTUM DYNAMICS

This paper considers the feasibility of creating dispersion-free solit ary quantum-mechanical wave packets. The analysis is carried out withi n a general framework of quantum-optimal control theory. A key to the realization of solitary quantum wave packets is the ability to create traveling wave potentials U(x - nu t) with coordinated space and time dependence where nu is a characteristic speed. As an illustration, the case of an atom translating in a designed optical trap is considered. Three examples are treated within this framework: (A) the motion of a dispersion-free traveling bound state, (B) feedback-stabilized solito nic motion, and (C) feedback-stabilized solitonic motion in the presen ce of auxiliary physical objectives. The quantum solitons of (B) and ( C) satisfy a nonlinear Schrodinger-type equation with laboratory feedb ack in the form of an observation of the probability density. This fee dback is essential for maintaining the solitonic-type motion. Some gen eralizations and potential applications of these concepts are also dis cussed.