Quantum trajectories for resonant scattering

Time-dependent wave packet resonant scattering for the double square barrie r has been studied in terms of Bohm quantum trajectories. The high transmis sion probability for the wave packet with a resonant energy can be explaine d by the behavior of the quantum trajectories under the influence of the re latively slow formation of a node within the first barrier. This node split s the trajectories into reflected and transmitted components. During this s tage, many particle trajectories pass through the double-barrier region and contribute to the transmitted part of the wave packet. Due to the transien t nature of the nodes, trajectories in the reflected wave packet bunch toge ther between the nodes for a finite period of time so that temporary struct ure (localization of particles and accompanying increase in the probability density) develops on small length scales. These calculations also show tha t the particles gain high momentum near the nodal points, and they reach a uniform momentum distribution after transmitting the barrier region. We hav e found that the presence of a node between the two barriers influences the different lifetimes of the quasi-bound states. (C) 2001 John Wiley & Sons, Inc.