Photoinduced dynamics of organic molecules using nonequilibrium Green's functions with second-Born, $GW$, $T$-matrix and three-particle ladder correlations

TL;DR

This paper develops a unifying, efficient NEGF framework incorporating advanced many-body correlations to accurately simulate ultrafast photoinduced dynamics in organic molecules, overcoming limitations of existing methods.

Contribution

It introduces a Faddeev-based NEGF scheme that includes three-particle correlations, significantly improving simulation accuracy and scalability for large molecular systems.

Findings

Faddeev NEGF scheme outperforms traditional methods in accuracy.

The new approach scales linearly with propagation time.

Demonstrated effectiveness on a solvable molecular model.

Abstract

The ultrafast hole dynamics triggered by the photoexcitation of molecular targets is a highly correlated process even for those systems, like organic molecules, having a weakly correlated ground state. We here provide a unifying framework and a numerically efficient matrix formulation of state-of-the-art non-equilibrium Green's function (NEGF) methods like second-Born as well as $GW$ and $T$-matrix without and {\em with} exchange diagrams. Numerical simulations are presented for a paradigmatic, exactly solvable molecular system and the shortcomings of the established NEGF methods are highlighted. We then develop a NEGF scheme based on the Faddeev treatment of three-particle correlations; the exceptional improvement over established methods is explained and demonstrated. The Faddeev NEGF scheme scales linearly with the maximum propagation time, thereby opening prospects for femtosecond simulations of large molecules.