Physical Review A
Time dependence of the probability density in the transient regime for tunneling
Gastón García‐Calderón, Jorge Villavicencio
Abstract
An exact analytical solution to the time-dependent Schr\"odinger equation with cutoff wave initial conditions is used to investigate the fast tunneling response of a rectangular potential barrier. We find that just across the tunneling region, the probability density exhibits at short times a transient behavior that may be characterized by a peak ${t}_{p}$ and a width $\ensuremath{\Delta}t.$ We show that ${t}_{p}$ provides the earliest tunneling response of the system and that the top-barrier S-matrix poles play an important role in the process. As a function of the barrier width, ${t}_{p}$ exhibits two regimes. Along the first regime, ${t}_{p}$ remains almost a constant; as the barrier width increases, a second regime appears where ${t}_{p}$ grows linearly with the barrier width.