Strong Field Ionization as an Inhomogeneous Schroedinger Equation

TL;DR

This paper introduces an inhomogeneous Schrödinger equation approach to improve the theoretical treatment of strong field ionization by decomposing the TDSE into bound and continuum components, enhancing accuracy and gauge invariance.

Contribution

It presents a novel inhomogeneous formulation of the TDSE that accurately models strong field ionization and clarifies gauge dependence issues in existing theories.

Findings

Equivalent to full TDSE with exact propagation

Reduces wavefunction errors with approximate propagation

Clarifies gauge invariance in strong field theories

Abstract

Strong field ionization is difficult to treat theoretically due to the simultaneous need to treat bound state dynamics accurately and continuum dynamics efficiently. We address this problem by decomposing the time dependent Schroedinger equation (TDSE) into an inhomogeneous form, in which a precomputed bound state acts as a source term for a time dependent tunneling component. The resulting theory is equivalent to the full TDSE when exact propagation is used, and reduces or eliminates a major source of wavefunction error when propagation is approximated. The gauge invariance of the resulting theory is used to clarify an apparent gauge dependence which has long been observed in the context of strong field S-matrix theory.