Dynamics of a quantum wave emitted by a decaying and evanescent point source

We put forward a model that describes a decaying and evanescent point source of non interacting quantum waves in 1D. This point source assumption allows for a simple description that captures the essential aspects of the dynamics of a wave traveling through a classically forbidden region without the need to specify the details of the inner region. The dynamics of the resulting wave is examined and several characteristic Limes are identified. One of them generalizes the tunneling time scale introduced by Buttiker and Landauer and it characterizes the arrival of the maximum of the wave function. Diffraction in time and deviations horn exponential decay are also studied. Here we show that there exists an optimal injection frequency and detection point for the observation of these two quantum phenomena. (C) 2015 Elsevier B.V. All rights reserved.