Exterior complex scaling as a perfect absorber in time-dependent problems

TL;DR

Exterior complex scaling effectively absorbs outgoing flux in time-dependent Schrödinger equation simulations, enabling accurate modeling of high harmonic generation and atomic responses in strong infrared fields.

Contribution

This paper demonstrates the application of exterior complex scaling as a perfect absorber in time-dependent quantum problems, providing implementation guidelines and efficiency criteria.

Findings

Complete absorption of outgoing flux achieved

High harmonic spectra match exact solutions

Applicable to 1D and 3D atomic systems

Abstract

It is shown that exterior complex scaling provides for complete absorption of outgoing flux in numerical solutions of the time-dependent Schr\"odinger equation with strong infrared fields. This is demonstrated by computing high harmonic spectra and wave-function overlaps with the exact solution for a one-dimensional model system and by three-dimensional calculations for the H atom and a Ne atom model. We lay out the key ingredients for correct implementation and identify criteria for efficient discretization.