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Auteurs principaux: Rook, T., Habibović, D., Faria, C. Figueira de Morisson
Format: Preprint
Publié: 2024
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Accès en ligne:https://arxiv.org/abs/2410.01058
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author Rook, T.
Habibović, D.
Faria, C. Figueira de Morisson
author_facet Rook, T.
Habibović, D.
Faria, C. Figueira de Morisson
contents Orbit-based methods are widespread in strong-field laser-matter interaction. They provide a framework in which photoelectron momentum distributions can be interpreted as the quantum interference between different semi-classical pathways the electron can take on its way to the detector, which brings with it great predictive power. The transition amplitude of an electron going from a bound state to a final continuum state is often written as multiple integrals, which can be computed either numerically, or by employing the saddle-point method. If one computes the momentum distribution via a saddle-point method, the obtained distribution is highly dependent on the time window from which the saddle points are selected for inclusion in the "sum over paths". In many cases, this leads to the distributions not even satisfying the basic symmetry requirements and often containing many more oscillations and interference fringes than their numerically integrated counterparts. Using the strong-field approximation, we find that the manual enforcement of the energy-conservation condition on the momentum distribution calculated via the saddle-point method provides a unique momentum distribution which satisfies the symmetry requirements of the system and which is in a good agreement with the numerical results. We illustrate our findings using the example of the Ar atom ionized by a selection of monochromatic and bichromatic linearly polarized fields.
format Preprint
id arxiv_https___arxiv_org_abs_2410_01058
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Energy-conservation conditions in saddle-point approximation for the strong-field-ionization of atoms
Rook, T.
Habibović, D.
Faria, C. Figueira de Morisson
Atomic Physics
Orbit-based methods are widespread in strong-field laser-matter interaction. They provide a framework in which photoelectron momentum distributions can be interpreted as the quantum interference between different semi-classical pathways the electron can take on its way to the detector, which brings with it great predictive power. The transition amplitude of an electron going from a bound state to a final continuum state is often written as multiple integrals, which can be computed either numerically, or by employing the saddle-point method. If one computes the momentum distribution via a saddle-point method, the obtained distribution is highly dependent on the time window from which the saddle points are selected for inclusion in the "sum over paths". In many cases, this leads to the distributions not even satisfying the basic symmetry requirements and often containing many more oscillations and interference fringes than their numerically integrated counterparts. Using the strong-field approximation, we find that the manual enforcement of the energy-conservation condition on the momentum distribution calculated via the saddle-point method provides a unique momentum distribution which satisfies the symmetry requirements of the system and which is in a good agreement with the numerical results. We illustrate our findings using the example of the Ar atom ionized by a selection of monochromatic and bichromatic linearly polarized fields.
title Energy-conservation conditions in saddle-point approximation for the strong-field-ionization of atoms
topic Atomic Physics
url https://arxiv.org/abs/2410.01058