DRIVEN QUANTUM TUNNELING

A contemporary review on the behavior of driven tunneling in quantum s ystems is presented. Diverse phenomena, such as control of tunneling, higher harmonic generation, manipulation of the population dynamics an d the interplay between the driven tunneling dynamics and dissipative effects are discussed. In the presence of strong driving fields or ult rafast processes, well-established approximations such as perturbation theory or the rotating wave approximation have to be abandoned. A var iety of tools suitable for tackling the quantum dynamics of explicitly time-dependent Schrodinger equations are introduced. On the other han d, a real-time path integral approach to the dynamics of a tunneling p article embedded in a thermal environment turns out to be a powerful m ethod to treat in a rigorous and systematic way the combined effects o f dissipation and driving. A selection of applications taken from the fields of chemistry and physics are discussed, that relate to the cont rol of chemical dynamics and quantum transport processes, and which al l involve driven tunneling events. (C) 1998 Elsevier Science B.V. All rights reserved.