An adaptive configuration interaction approach for strongly correlated electrons with tunable accuracy

TL;DR

The paper presents an adaptive configuration interaction method that iteratively selects determinant spaces to accurately describe strongly correlated electrons with tunable precision.

Contribution

It introduces a novel iterative selection procedure for determinant spaces with importance criteria, enabling controlled accuracy in strongly correlated systems.

Findings

Accurately predicts potential energy curves of N₂ with nearly constant errors.

Provides singlet-triplet splittings of acenes in good agreement with DMRG.

Demonstrates tunable accuracy in describing strongly correlated electrons.

Abstract

We introduce a new procedure for iterative selection of determinant spaces capable of describing highly correlated systems. This adaptive configuration interaction (ACI) determines an optimal basis by an iterative procedure in which the determinant space is expanded and coarse grained until self consistency. Two importance criteria control the selection process and tune the ACI to a user-defined level of accuracy. The ACI is shown to yield potential energy curves of N$_2$ with nearly constant errors, and it predicts singlet-triplet splittings of acenes up to decacene that are in good agreement with the density matrix renormalization group.