Many-body Green's function approach to attosecond nonlinear X-ray spectroscopy

TL;DR

This paper develops a Green's function-based theoretical framework for resonant multidimensional X-ray spectroscopy, enabling the prediction of nonlinear signals involving core-hole states with potential applications in attosecond science.

Contribution

It introduces a novel formalism using quasiparticle nonlinear exciton representation and Green's functions to analyze nonlinear X-ray signals involving core-holes.

Findings

Derived closed-form expressions for resonant multidimensional X-ray signals.

Predicted coherent four-wave mixing signals probing core-hole states.

Expressed nonlinear signals in terms of Green's functions obtainable from Hedin-like equations.

Abstract

Closed expressions are derived for resonant multidimensional X-ray spectroscopy using the quasiparticle nonlinear exciton representation of optical response. This formalism is applied to predict coherent four wave mixing signals which probe single and two core-hole states. Nonlinear X-ray signals are compactly expressed in terms of one- and two- particle Green's functions which can be obtained from the solution of Hedin-like equations at the $GW$ level.