A NEW TIME-SCALE FOR TUNNELING

We study the tunneling through an oscillating delta barrier. Using tim e periodicity of the model, the time-dependent Schrodinger equation is reduced to a simple but infinite matrix equation. Employing Toeplitz matrix methods, the infinite matrix is replaced by a 3 x 3 matrix, all owing an analytical solution. Looking at the frequency dependence of t he transmission amplitudes, one observes a new time scale which domina tes the tunneling dynamics. This time scale differs from the one previ ously introduced by Buttiker and Landauer. The relation between these two is discussed.