Quantum-Information Measure of Electron Localization
Abstract
Understanding electron localization in molecules and materials plays a central role in electronic structure theory, and will increase in importance with the rise of data-driven approaches. The electron localization function (ELF) is widely used to visualize electron organization in molecules and materials, and it remains a central ingredient in modern density-functional approximations. Yet its formulation retains highly empirical elements. Here we introduce a quantum-information measure of electron localization derived from the concurrence of a correlated two-spin mixed state. This construction yields a genuine two-point localization indicator grounded in quantum-information theory, avoiding the heuristic normalization and chosen nonlinear remapping of the ELF. We show that atomic shells, covalent and ionic bonds, lone pairs, molecular dissociation, and charge-transfer processes are captured. The method is straightforward to evaluate numerically.
Cite
@article{arxiv.2604.01688,
title = {Quantum-Information Measure of Electron Localization},
author = {Stefano Pittalis and Filippo Troiani and Celestino Angeli and Irene D'Amico and Tim Gould},
journal= {arXiv preprint arXiv:2604.01688},
year = {2026}
}