Quantum information analysis of electronic states at different molecular structures

TL;DR

This paper applies quantum information theory and DMRG methods to study electronic states in transition metal clusters, highlighting the role of entanglement and proposing efficient computational strategies.

Contribution

It introduces a new approach combining quantum information theory with DMRG to analyze molecular electronic structures, improving efficiency and understanding of entanglement effects.

Findings

Entanglement influences orbital interactions significantly.

The dynamically extended active space accelerates convergence.

A black-box DMRG calculation recipe is proposed.

Abstract

We have studied transition metal clusters from a quantum information theory perspective using the density-matrix renormalization group (DMRG) method. We demonstrate the competition between entanglement and interaction localization. We also discuss the application of the configuration interaction based dynamically extended active space procedure which significantly reduces the effective system size and accelerates the speed of convergence for complicated molecular electronic structures to a great extent. Our results indicate the importance of taking entanglement among molecular orbitals into account in order to devise an optimal orbital ordering and carry out efficient calculations on transition metal clusters. We propose a recipe to perform DMRG calculations in a black-box fashion and we point out the connections of our work to other tensor network state approaches.