Nonequilibrium diagrammatic technique for Hubbard Green functions

TL;DR

This paper presents a diagrammatic method for calculating Hubbard nonequilibrium Green functions, enabling accurate modeling of strongly correlated molecular junctions with exact intra-system interactions and perturbative contact coupling.

Contribution

It introduces a novel diagrammatic technique extending equilibrium Hubbard Green functions to nonequilibrium systems, specifically for molecular junctions.

Findings

Successfully applied to a quantum dot model with two reservoirs

Demonstrates accurate treatment of intra-system interactions

Validates approach with numerical simulations

Abstract

We introduce diagrammatic technique for Hubbard nonequilibrium Green functions (NEGF). The formulation is an extension of equilibrium considerations for strongly correlated lattice models to description of current carrying molecular junctions. Within the technique intra-system interactions are taken into account exactly, while molecular coupling to contacts is used as a small parameter in perturbative expansion. We demonstrate the viability of the approach with numerical simulations for a generic junction model of quantum dot coupled to two electron reservoirs.