Simulating one hundred entangled atoms using projected-interacting full configuration interaction wavefunctions corrected by projected density functionals

TL;DR

This paper presents a novel wavefunction method, PiFCI+DFT, for simulating large entangled atomic systems, enabling detailed analysis of entanglement and strong correlation with high accuracy.

Contribution

It introduces PiFCI+DFT, a new approach combining full configuration interaction with density functional theory to efficiently simulate large entangled systems.

Findings

Successfully applied to a 300-electron active space

Achieves near-exact correlated wavefunctions

Maintains competitive accuracy for molecular properties

Abstract

Simulating entangled atoms is a prerequisite to modeling quantum materials and remains an outstanding challenge for theory. I introduce a correlated wavefunction approach capable of simulating large entangled systems, and demonstrate its application to a 300-electron active space. Projected-interacting full configuration interaction plus density functional theory PiFCI+DFT combines near-exact correlated wavefunctions of multiple partially-interacting model systems, each corrected by a formally exact density functional. This approach can access large active spaces and visualize entanglement and strong correlation while maintaining competitive accuracy for molecular properties.