Systematic improvability in quantum embedding for real materials

TL;DR

This paper introduces a quantum embedding method that enables systematic convergence of properties in real materials, achieving high accuracy without empirical parameters across various regimes.

Contribution

It develops a quantum embedding theory combining density-matrix embedding with local correlation methods, ensuring systematic improvability with a single rapid parameter.

Findings

Accurately predicts structural and electronic properties of solids.

Achieves state-of-the-art agreement with experimental data.

Works across insulating, semi-metallic, and strongly correlated regimes.

Abstract

Quantum embedding methods have become a powerful tool to overcome deficiencies of traditional quantum modelling in materials science. However, while these are systematically improvable in principle, in practice it is rarely possible to achieve rigorous convergence and often necessary to employ empirical parameters. Here, we formulate a quantum embedding theory, building on the methods of density-matrix embedding theory combined with local correlation approaches from quantum chemistry, to ensure the ability to systematically converge properties of real materials with accurate correlated wave~function methods, controlled by a single, rapidly convergent parameter. By expanding supercell size, basis set, and the resolution of the fluctuation space of an embedded fragment, we show that the systematic improvability of the approach yields accurate structural and electronic properties of realistic solids without empirical parameters, even across changes in geometry. Results are presented in insulating, semi-metallic, and more strongly correlated regimes, finding state of the art agreement to experimental data.