Density Matrix Renormalization Group Approach Based on the Coupled-Cluster Downfolded Hamiltonians

TL;DR

This paper introduces a novel combined approach using coupled-cluster downfolded Hamiltonians with DMRG to better capture both static and dynamic electron correlations in complex molecular systems, improving accuracy in electronic structure calculations.

Contribution

It develops a new method integrating coupled-cluster downfolding with DMRG, enhancing the treatment of dynamic correlation effects in strongly correlated systems.

Findings

Accurate ground-state energies for N₂, benzene, and TME.

Improved description of static and dynamic correlations.

Demonstrated efficiency over traditional methods.

Abstract

The Density Matrix Renormalization Group (DMRG) method has become a prominent tool for simulating strongly correlated electronic systems characterized by dominant static correlation effects. However, capturing the full scope of electronic interactions, especially for complex chemical processes, requires an accurate treatment of static and dynamic correlation effects, which remains a significant challenge in computational chemistry. This study presents a new approach integrating a Hermitian coupled-cluster-based downfolding technique, incorporating dynamic correlation into active-space Hamiltonians, with the DMRG method. By calculating the ground-state energies of these effective Hamiltonians via DMRG, we achieve a more comprehensive description of electronic structure. We demonstrate the accuracy and efficiency of this combined method for advancing simulations of strongly correlated systems using benchmark calculations on molecular systems, including N$_2$, benzene, and tetramethyleneethane (TME).