THE EVOLUTION AND REVIVAL STRUCTURE OF LOCALIZED QUANTUM WAVE-PACKETS

Localized quantum wave packets can be produced in a variety of physica l systems and are the subject of much current research in atomic, mole cular, chemical, and condensed-matter physics. They are particularly w ell suited for studying the classical limit of a quantum-mechanical sy stem. The motion of a localized quantum wave packet initially follows the corresponding classical motion, However, in most cases the quantum wave packet spreads and undergoes a series of collapses and revivals. We present a generic treatment of wave-packet evolution, and we provi de conditions under which various types of revivals occur in ideal for m. The discussion is at a level appropriate for an advanced undergradu ate or first-year graduate course in quantum mechanics, Explicit examp les of different types of revival structure are provided, and physical applications are discussed. (C) 1996 American Association of Physics Teachers.