Clifford augmented density matrix renormalization group for \textit{ab initio} quantum chemistry

TL;DR

This paper introduces an efficient CA-DMRG method for extit{ab initio} quantum chemistry, combining Clifford circuits with matrix product states to improve accuracy in molecular simulations with moderate computational cost.

Contribution

The authors develop a new scheme in CA-DMRG tailored for quantum chemistry Hamiltonians, demonstrating enhanced accuracy over standard DMRG for molecular systems.

Findings

CA-DMRG achieves higher accuracy than DMRG at the same bond dimension

The method effectively handles strong static correlations in molecules

Numerical results show promising potential for quantum chemistry applications

Abstract

The recently proposed Clifford augmented density matrix renormalization group (CA-DMRG) method seamlessly integrates Clifford circuits with matrix product states, and takes advantage of the expression power from both. CA-DMRG has been shown to be able to achieve higher accuracy than standard DMRG on commonly used lattice models, with only moderate computational overhead compared to the latter. In this work, we propose an efficient scheme in CA-DMRG to deal with \textit{ab initio} quantum chemistry Hamiltonians, and apply it to study several molecular systems. Our numerical results show that CA-DMRG can reach higher accuracy than DMRG using the same bond dimension, pointing out a promising route to push the boundary of solving \textit{ab initio} quantum chemistry with strong static correlations.