Dynamically assisted tunneling in the impulse regime

Abstract

We study the enhancement of tunneling through a potential barrier V(x) by a time-dependent electric field with special emphasis on pulse-shaped vector potentials such as Ax(t)=A0/cosh2(ωt). In addition to the known effects of preacceleration and potential deformation already present in the adiabatic regime, as well as energy mixing in analogy to the Franz-Keldysh effect in the nonadiabatic (impulse) regime, the pulse Ax(t) can enhance tunneling by "pushing"part of the wave function out of the rear end of the barrier. Aside from the natural applications in condensed matter and atomic physics, these findings could be relevant for nuclear fusion, where pulses Ax(t) with ω=1keV and peak field strengths of 1016V/m might enhance tunneling rates significantly.