Unity of Kohn-Sham density-functional theory and reduced-density-matrix-functional theory

This work presents a theory to unify the two independent theoretical frameworks of Kohn-Sham (KS) density functional (DFT) and reduced matrix (RDMFT). The generalization KS orbitals hypercomplex number systems leads (HCKS) theory, which extends search space for in KS-DFT that is equivalent natural spin with fractional occupations RDMFT. Thereby, HCKS able capture multi-reference nature strong correlation by dynamically varying occupations. Moreover, potential overcome fundamental limitations verified on correlation, including atoms transition metals. As promising alternative realization DFT, opens up new possibilities development application DFT future.