Work

High-order strong-coupling expansion for x-ray absorption on a dynamically screened impurity

Year: 2025

Type: article

Abstract: Time-resolved x-ray absorption can reveal the dynamical screening of the local Coulomb interaction in strongly correlated photodoped materials. Here, we focus on the theoretical prediction of x-ray absorption in the presence of dynamical screening using the strong-coupling expansion, i.e., an expansion around the isolated absorption site in terms of the retarded interaction. The evaluation of higher-order diagrams is made numerically feasible by an approach based on the decomposition of the retarded interaction into complex exponentials. With this, we evaluate the strong-coupling series to third order on an electron-boson model of Holstein type. We demonstrate that in relevant coupling regimes, even low orders of the strong-coupling expansion can give a significant correction over the previously used lowest-order approximation.

Source: Physical review. B./Physical review. B

DOI: 10.1103/bl6z-14m9

Authors: Eva Paprotzki, Martin Eckstein

Institutions: Universität Hamburg, Hamburg Centre for Ultrafast Imaging

Language: English

Topic: Physics of Superconductivity and Magnetism

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funder: Deutsche Forschungsgemeinschaft

Awards: G1230266125, EXC 2056: CUI: Advanced Imaging of Matter, G5631081224