Quasipinning and selection rules for excitations in atoms and molecules

Abstract

Postulated by Pauli to explain the electronic structure of atoms and molecules, the exclusion principle establishes an upper bound of 1 for the fermionic natural occupation numbers $\{n_i\}$. A recent analysis of the pure $N$-representability problem provides a wide set of inequalities for the $\{n_i\}$, leading to constraints on these numbers. This has a strong potential impact on reduced density matrix functional theory as we know it. In this work we continue our study the nature of these inequalities for some atomic and molecular systems. The results indicate that (quasi)saturation of some of them leads to selection rules for the dominant configurations in configuration interaction expansions, in favorable cases providing means for significantly reducing their computational requirements.

arXiv comment12 pages, 15 figures, new references, some typos corrected and a new section added

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Cited by in corpus (23)

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• Spectral properties of reduced fermionic density operators and parity superselection rule
• Reconstructing quantum states from single-party information
• Generalized Pauli constraints in small atoms
• Pinning of Fermionic Occupation Numbers: General Concepts and One Dimension
• Experimental Data from a Quantum Computer Verifies the Generalized Pauli Exclusion Principle
• Influence of the Fermionic Exchange Symmetry beyond Pauli's Exclusion Principle
• Pinning of fermionic occupation numbers: Higher spatial dimensions and spin
• Natural Extension of Hartree-Fock through extremal $1$-fermion information: Overview and application to the lithium atom
• Asymptotic properties of entanglement polytopes for large number of qubits
• Role of the pair potential for the saturation of generalized Pauli constraints
• Static correlated functionals for reduced density matrix functional theory
• On the time evolution of fermionic occupation numbers
• Implications of pinned occupation numbers for natural orbital expansions. I: Generalizing the concept of active spaces
• Quantum marginals from pure doubly excited states
• Optimal Slater-determinant approximation of fermionic wave functions
• Potential energy curve for the $a^3{\Sigma }_u^{+}$ state of lithium dimer with Slater-type orbitals
• Conditions for describing triplet states in reduced density matrix functional theory
• Structure of the first order Reduced Density Matrix in three electron systems: A Generalized Pauli Constraints assisted study
• A toolbox of spin-adapted generalized Pauli constraints
• Quantum Simulation of Molecules without Fermionic Encoding of the Wave Function