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O: Fachverband Oberflächenphysik

O 10: Focus Session: Frontiers of Electronic-Structure Theory – Advances in Time-Dependent and Nonequilibrium Ab Initio Methods II

O 10.5: Talk

Monday, March 18, 2024, 16:00–16:15, HE 101

Multi-channel Dyson equation: coupling many-body Green’s functions — •Arjan Berger — Paul Sabatier University, Toulouse, France

We present the multichannel Dyson equation that combines two or more many-body Green’s functions to describe the electronic structure of materials. In this work we use it to model photoemission spectra by coupling the one-body Green’s function with the three-body Green’s function. We demonstrate that, unlike methods using only the one-body Green’s function, our approach puts the description of quasi-particles and satellites on an equal footing. We propose a multichannel self-energy that is static and only contains the bare Coulomb interaction, making frequency convolutions and self-consistency unnecessary. Despite its simplicity, we demonstrate with a diagrammatic analysis that the physics it describes is extremely rich. Finally, we present a framework based on an effective Hamiltonian that can be solved for any many-body system using standard numerical tools.

References:
G. Riva, P. Romaniello, and J. A. Berger, Phys. Rev. Lett. 131, 216401 (2023)
G. Riva, T. Audinet, M. Vladaj, P. Romaniello, and J. A. Berger, SciPost Phys. 12, 093 (2022)

Keywords: photoemission; Green's function; electronic structure; ab initio theory