QED theory of the multiphoton cascade transitions in atoms

TL;DR

This paper develops a QED-based theoretical framework for multiphoton cascade transitions in atoms, crucial for understanding astrophysical hydrogen recombination, and addresses existing controversies in the literature.

Contribution

It introduces an accurate QED theory for multiphoton cascade processes in atoms, resolving previous disagreements and enhancing astrophysical modeling.

Findings

Provides a detailed QED description of specific multiphoton transitions

Resolves controversies regarding multiphoton cascade processes

Enhances understanding of hydrogen recombination in cosmology

Abstract

QED theory of multiphoton cascade transitions in atoms and ions is developed. This theory allows for the accurate description of the process important for astrophysical studies of the cosmological hydrogen recombination. In particular the $ 3s\rightarrow1s+2\gamma $, $ 4s\rightarrow1s+2\gamma $ and $ 3p\rightarrow1s+3\gamma $ processes are considered and some controversies existing in the literature are resolved.