Akademik Veri Yönetim Sistemi
Physical Review Research, cilt.7, sa.2, 2025 (ESCI, Scopus)
We establish a toolbox for studying and applying spin-Adapted generalized Pauli constraints (GPCs) in few-electron quantum systems. By exploiting the spin symmetry of realistic N-electron wave functions, the underlying one-body pure N-representability problem simplifies, allowing us to calculate the GPCs for larger system sizes than previously accessible. We then uncover and rigorously prove a superselection rule that highlights the significance of GPCs: whenever a spin-Adapted GPC is (approximately) saturated-referred to as (quasi)pinning-the corresponding N-electron wave function assumes a simplified structure. Specifically, in a configuration interaction expansion based on natural orbitals only very specific spin configuration state functions may contribute. To assess the nontriviality of (quasi)pinning, we introduce a geometric measure that contrasts it with the (quasi)pinning induced by simple (spin-Adapted) Pauli constraints. Applications to few-electron systems suggest that previously observed quasipinning largely stems from spin symmetries.