Dynamically assisted tunneling in the impulse regime

TL;DR

This paper investigates how specific time-dependent electric field pulses can significantly enhance quantum tunneling rates, with potential applications in condensed matter, atomic physics, and nuclear fusion.

Contribution

It introduces a detailed analysis of pulse-shaped vector potentials, revealing new mechanisms for tunneling enhancement beyond known effects.

Findings

Pulse A_x(t) can push wave-functions out of barriers.

Enhancement effects observed in both adiabatic and non-adiabatic regimes.

Potential for significant tunneling rate increases in nuclear fusion scenarios.

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 $A_x(t)=A_0/\cosh^2(\omega t)$. In addition to the known effects of pre-acceleration and potential deformation already present in the adiabatic regime, as well as energy mixing in analogy to the Franz-Keldysh effect in the non-adiabatic (impulse) regime, the pulse $A_x(t)$ can enhance tunneling by ``pushing'' part of the wave-function out of the rear end of the barrier. Besides the natural applications in condensed matter and atomic physics, these findings could be relevant for nuclear fusion, where pulses $A_x(t)$ with $\omega=1~\rm keV$ and peak field strengths of $10^{16}~\rm V/m$ might enhance tunneling rates significantly.