Although Hartree-Fock theory provides a feasible and computationally inexpensive approach to electronic structure calculations, the mean-field approximation completely neglects electron correlation, both static and dynamic. Electron correlation is crucial for accurately describing chemical reactions, non-covalent interactions, and, in particular, strongly correlated systems such as those containing transition metals. To address these limitations, correlated theories such as Coupled Cluster Singles, Doubles, and Perturbative Triples (CCSD(T)) and Configuration Interaction methods have been developed. However, the steep scaling of these methods with system size limits their applicability to large systems.