Wave Packets

John A. Yeazell, T. Uzer

Wave Packets: Past and Present (M. Nauenberg). Semiclassical Wave Packets (E. Heller). Excitation of Atomic Wave Packets (J. Yeazell). From Asteroids to Atoms: Quantum Wave Packets and the Restricted Three--Body Problem of Celestial Mechanics (E. Lee, et al.). Destruction of Quantum Coherence and Wave Packet Dynamics (G. Alber). Wave Packets and Half--Cycle Pulses (P. Bucksbaum). Exploring Phase Space with Wave Packets (F. Borondo & R. Benito). Wave Packet Dynamics in Small Molecules (M. Braun, et al.). Time Dependent and Time Independent Wave Packet Approaches to Reactive Scattering (S. Althorpe, et al.). Laser--Excited Wave Packets in Semiconductor Heterostructures (K. Leo & M. Koch). Index.

Robert Bluhm, V. Alan Kostelecký, Bogdan Tudose

We examine the revival structure of Rydberg wave packets. These wave packets exhibit initial classical periodic motion followed by a sequence of collapse, fractional/full revivals, and fractional/full superrevivals. The effects of quantum defects on wave packets in alkali-metal atoms and a squeezed-state description of the initial wave packets are also described. We then examine the revival structure of Rydberg wave packets in the presence of an external electric field, i.e., the revival structure of Stark wave packets. These wave packets have energies that depend on two quantum numbers and exhibit new types of interference behavior.

Henry M. Bradford

The usual textbook discussions of the velocity and spreading of a wave packet are based on special cases and approximations which have a limited range of validity. In this paper more general relations are obtained by considering the time dependence of the moments of a wave packet. Both a packet of real sinusoidal plane waves (a real pulse, e.g., sound) and a packet of complex exponential plane waves (e.g., the quantum-mechanical wave function of a free particle) are considered. The results are similar if the real wave packet contains no standing wave components. It is shown that the centroid of a wave packet moves at a constant velocity which is a weighted average of the group velocity. The spreading of the wave packet depends on the product of the variance of the group velocity and the square of the time interval before or after the time of minimum packet width. The packet moves and spreads like a collection of particles in free flight, in which the velocities of the particles are the group velocities of the wave components of the packet.

Ciprian Demeter