Nonequilibrium Green function approach to photoionization processes in atoms

TL;DR

This paper introduces a quantum kinetic method using non-equilibrium Green functions to model many-body effects in atomic photoionization, capturing continuum dynamics and correlations.

Contribution

It develops a novel approach combining the Keldysh/Kadanoff-Baym equations with an approximation scheme for correlated atomic systems.

Findings

Provides a comprehensive single-particle continuum description

Fully accounts for many-body correlations in atoms

Enables time-resolved analysis of photoionization processes

Abstract

We present a quantum kinetic approach for the time-resolved description of many-body effects in photoionization processes in atoms. The method is based on the non-equilibrium Green functions formalism and solves the Keldysh/Kadanoff-Baym equations in second Born approximation. An approximation scheme is introduced and discussed, which provides a complete single-particle description of the continuum, while the atom is treated fully correlated.