Exact Conditions for Ensemble Density Functional Theory

2023/07/01 by Thais R. Scott, John F. Kozlowski, Scott, Thais R. +7 · 5 citations
Chemical Engineering · Physics and Astronomy · #Advanced Chemical Physics Studies #Catalysis and Oxidation Reactions #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Spectroscopy and Quantum Chemical Studies #Strongly Correlated Electrons (cond-mat.str-el)

paper · pdf · doi:10.48550/arxiv.2307.00187

openalex publication_date 2023/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Ensemble density functional theory (EDFT) is a promising alternative to time-dependent density functional theory for computing electronic excitation energies. Using coordinate scaling, we prove several fundamental exact conditions in EDFT and illustrate them on the exact singlet bi-ensemble of the Hubbard dimer. Several approximations violate these conditions, and some ground-state conditions from quantum chemistry do not generalize to EDFT. The strong-correlation limit is derived for the dimer, revealing weight-dependent derivative discontinuities in EDFT.

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