Tunnelling time of a gaussian wave packet through two potential barriers

The resonant and non-resonant dynamics of a Gaussian quantum wave packet travelling through a double barrier system is studied as a function of the initial characteristics of the spectrum and of the parameters of the potential. The behaviour of the tunnelling time shows that there are situations where the Hartman effect occurs,while, when the resonances are dominant, and in particular for b> pi/Delta k(b being the inter-barrier distance and Delta k the spectrum width), the tunnelling time becomes very large and the Hartman effect does not take place. (C) Central European Science Journals. All rights reserved.