Benchmark of few-level quantum theory vs ab initio numerical solutions for the strong-field Autler–Townes effect in photoionization of hydrogen

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2022-08, Vol.55 (16), p.164001
• Main Authors: Younis, D, Eberly, J H
• Format: Article
• Language: English
• Subjects: Autler–Townes effect; field-dressed atomic states; hydrogen electron wavefunction; Numerical time-dependent Schrödinger equation; resonant photoionization
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/1361-6455/ac7d7f

The temporal and spectral consequences of an intermediate resonance en route to photoionization are investigated theoretically in two ways: by solving few-level model equations and by ab initio numerical solution of the time-dependent Schrödinger equation, in both cases for hydrogen in three dimensions. The model consists of atomic states resonantly field-dressed in a three-level reduction of the hydrogen atom that consists of the 2 p –3 d (Balmer) transition and one energetically-distant continuum state. The model’s level occupation probabilities are derived from three Schrödinger amplitude equations and are benchmarked against an ab initio numerical solution for the hydrogen electron’s wavefunction under the same field. We examine contrasts between the results of the two approaches with a particular focus on Autler–Townes doublets that appear in the photoelectron spectrum.