Natural Extension of Hartree-Fock through extremal $1$-fermion information: Overview and application to the lithium atom

Abstract

Fermionic natural occupation numbers do not only obey Pauli's exclusion principle but are even stronger restricted by so-called generalized Pauli constraints. Whenever given natural occupation numbers lie on the boundary of the allowed region the corresponding $N$-fermion quantum state has a significantly simpler structure. We recall the recently proposed natural extension of the Hartree-Fock ansatz based on this structural simplification. This variational ansatz is tested for the lithium atom. Intriguingly, the underlying mathematical structure yields universal geometrical bounds on the correlation energy reconstructed by this ansatz.

Contribution to the special issue dedicated to professor Michael Springborg on the occasion of his 60th birthday, 7 pages

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Cited by in corpus (7)

• Towards a formal definition of static and dynamic electronic correlations
• Non-equilibrium Steady State Conductivity in Cyclo[18]carbon and Its Boron Nitride Analogue
• Quantum-classical hybrid algorithm using an error-mitigating $N$-representability condition to compute the Mott metal-insulator transition
• Relating correlation measures: the importance of the energy gap
• Experimental Data from a Quantum Computer Verifies the Generalized Pauli Exclusion Principle
• Pinning of fermionic occupation numbers: Higher spatial dimensions and spin
• A toolbox of spin-adapted generalized Pauli constraints