Time scales of tunneling decay of a localized state
- Department of Physical Chemistry, Universidad del Pais Vasco UPV-EHU, E-48080 Bilbao (Spain)
- Departement de Physique Theorique, Universite de Geneve, CH-1211 Geneve 4 (Switzerland)
Motivated by recent time-domain experiments on ultrafast atom ionization, we analyze the transients and time scales that characterize, aside from the relatively long lifetime, the decay of a localized state by tunneling. While the tunneling starts immediately, some time is required for the outgoing flux to develop. This short-term behavior depends strongly on the initial state. For the initial state, tightly localized so that the initial transients are dominated by over-the-barrier motion, the time scale for flux propagation through the barrier is close to the Buettiker-Landauer traversal time. Then a quasistationary, slow-decay process follows, which sets ideal conditions for observing diffraction in time at longer times and distances. To define operationally a tunneling time at the barrier edge, we extrapolate backward the propagation of the wave packet that escaped from the potential. This extrapolated time is considerably longer than the time scale of the flux and density buildup at the barrier edge.
- OSTI ID:
- 21528829
- Journal Information:
- Physical Review. A, Vol. 82, Issue 6; Other Information: DOI: 10.1103/PhysRevA.82.062121; (c) 2010 American Institute of Physics; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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