Many-body $GW$ calculations with very large scale polarizable environments made affordable: a fully ab initio QM/QM approach

TL;DR

This paper introduces an efficient, fully ab initio many-body $GW$ method for large-scale polarizable environments, enabling accurate quantum calculations on systems with hundreds of thousands of atoms.

Contribution

It develops a fragment-based $GW$ approach with minimal susceptibility representation, significantly reducing computational cost while maintaining accuracy for large polarizable systems.

Findings

Successfully applied to fullerene bulk, surface, and slabs.

Achieved accurate results with reduced computational resources.

Demonstrated scalability to systems with hundreds of thousands of atoms.

Abstract

We present a many-body $GW$ formalism for quantum subsystems embedded in discrete polarizable environments containing up to several hundred thousand atoms described at a fully ab initio random phase approximation level. Our approach is based on a fragment approximation in the construction of the Green's function and independent-electron susceptibilities. Further, the environing fragments susceptibility matrices are reduced to a minimal but accurate representation preserving low order polarizability tensors through a constrained minimization scheme. This approach dramatically reduces the cost associated with inverting the Dyson equation for the screened Coulomb potential $W$, while preserving the description of short to long-range screening effects. The efficiency and accuracy of the present scheme is exemplified in the paradigmatic cases of fullerene bulk, surface, subsurface, and slabs with varying number of layers.