Natural Orbital Functional Theory is one of the long-standing methodological pillars of the Donostia Kimika Teorikoa Laboratory. The NOFT line develops reduced-density-matrix-based electronic structure methods that aim to describe electron correlation with a cost that scales more favorably than wavefunction approaches while keeping a rigorous N-representability framework.

The subgroup is led by Mario Piris and combines formal developments, algorithm design and software implementation through the DoNOF program. Current activity spans PNOF and GNOF developments, efficient large-scale implementations, strongly correlated systems, excited states and connections with modern quantum and data-driven strategies.