2022/02/11 by Ruiheng Song, Thomas M. Henderson, Gustavo E. Scuseria
Physics and Astronomy · #cond-mat.str-el #physics.chem-ph
paper · pdf · doi:10.1063/5.0080165
arxiv created 2022/02/11 · arxiv updated 2022/04/06
Projected Hartree-Fock theory provides an accurate description of many kinds of strong correlations but does not properly describe weakly-correlated systems. On the other hand, single-reference methods such as configuration interaction or coupled cluster theory can handle weakly-correlated problems but cannot properly account for strong correlations. Ideally, we would like to combine these approaches in a symmetry-projected coupled cluster approach, but this is far from straightforward. In this work, we provide an alternative formulation to identify the so-called disentangled cluster operators which arise when we combine these two methodological strands. Our formulation shows promising results for model systems and small molecules.