Merging Features from Green's Functions and Time Dependent Density Functional Theory: A Route to the Description of Correlated Materials out of Equilibrium?

TL;DR

This paper introduces a hybrid approach combining density functional theory and many-body perturbation theory to better describe nonequilibrium correlated materials, showing significant improvements over existing methods in various regimes.

Contribution

The paper presents a novel protocol that merges exchange-correlation potentials with self-energies to accurately model nonequilibrium systems, reducing double counting issues.

Findings

Significant improvement over adiabatic TDDFT and second Born NEGF in many regimes.

Effective in systems with varying interaction strength, perturbation speed, and inhomogeneity.

Validated against exact results in Hubbard-type models.

Abstract

We propose a description of nonequilibrium systems via a simple protocol that combines exchange-correlation potentials from density functional theory with self-energies of many-body perturbation theory. The approach, aimed to avoid double counting of interactions, is tested against exact results in Hubbard-type systems, with respect to interaction strength, perturbation speed and inhomogeneity, and system dimensionality and size. In many regimes, we find significant improvement over adiabatic time dependent density functional theory or second Born nonequilibrium Green's function approximations. We briefly discuss the reasons for the residual discrepancies, and directions for future work.