Optimizing Hartree-Fock orbitals by the density-matrix renormalization group

TL;DR

This paper introduces a DMRG-based method to optimize molecular orbitals, significantly enhancing accuracy and efficiency in quantum chemistry calculations, demonstrated by improved results for water molecule energies.

Contribution

It presents a novel DMRG scheme for optimizing one-electron basis states, advancing computational methods in quantum chemistry.

Findings

Optimized orbitals improve ground state energy accuracy.

DMRG scheme reduces the number of orbitals needed.

Results comparable to quantum Monte Carlo methods.

Abstract

We have proposed a density-matrix renormalization group (DMRG) scheme to optimize the one-electron basis states of molecules. It improves significantly the accuracy and efficiency of the DMRG in the study of quantum chemistry or other many-fermion system with nonlocal interactions. For a water molecule, we find that the ground state energy obtained by the DMRG with only 61 optimized orbitals already reaches the accuracy of best quantum Monte Carlo calculation with 92 orbitals.