Direct comparison of many-body methods for realistic electronic Hamiltonians

TL;DR

This paper benchmarks 20 advanced many-body electronic structure methods on transition metal atoms and their compounds, establishing reference energies and evaluating the accuracy of emerging scalable approaches.

Contribution

It provides a comprehensive comparison of many-body methods against experimental data, offering reference values and insights into their relative accuracies.

Findings

Three systematically converged methods agree closely, providing experiment-free reference energies.

Most accurate methods match experimental results within uncertainties.

Comparison offers new perspectives on many-electron system calculations.

Abstract

A large collaboration carefully benchmarks 20 first principles many-body electronic structure methods on a test set of 7 transition metal atoms, and their ions and monoxides. Good agreement is attained between the 3 systematically converged methods, resulting in experiment-free reference values. These reference values are used to assess the accuracy of modern emerging and scalable approaches to the many-electron problem. The most accurate methods obtain energies indistinguishable from experimental results, with the agreement mainly limited by the experimental uncertainties. Comparison between methods enables a unique perspective on calculations of many-body systems of electrons.