Kohn-Sham ensemble v-representability of Coulomb ground-state densities by potentials in L^{3/2}+L^infinity
Kohn-Sham density functional theory replaces an interacting electronic ground state by noninteracting electrons in a common local potential that reproduces its density. Levy and Lieb separated the existence of states with a prescribed density from the existence of a potential for which such states are ground states; ensembles of degenerate noninteracting ground states enlarge the class (Ullrich-Kohn). Explicit non-representable model densities and numerical violations are known, but not for an actual Coulomb system. Is the ground-state density of every finite Coulomb molecule the density of a ground-state ensemble of noninteracting electrons in some real local potential ?
- Result
- Disproved(see note)
- Status
- Candidate (review pending)
- AI contribution
- AI-discovered
- Method
- Construction
- Field
- Density functional theory; noninteracting v-representability
- Posed by
- Assumed by Kohn and Sham (1965); posed as the v-representability problem by Mel Levy (1979) and Elliott H. Lieb (Density functionals for Coulomb systems, 1983); reviewed by Penz et al. (2023)
- Year posed
- 1983
- Years open
- 43y
- Solved
- 2026-09-25
- Model
- Unreleased internal OpenAI model
- Vendor
- OpenAI
- Collaborators
- —
- Verification
- Unreviewed
- Publication
- Announced
- Collection
- OpenAI math release (October 2026), version adc7f12
- Significance
- 22 / 100
- Disclosed cost
- —
- Wikipedia
- No dedicated article
What was actually shown
Theorem 1.1: there is a finite positive integer such that the three-electron Coulomb Hamiltonian with two nuclei of charge at , , has a normalizable absolute ground state (sector ) whose spin-summed density is not the density of any ground-state ensemble of for any real . The mechanism is the Gori-Giorgi-Gal-Baerends nodal-plane asymptotics, made rigorous, plus a kinetic certificate against all ensembles. A corollary rules out a local-potential first variation of the ensemble Hartree-exchange-correlation functional at that density. Not covered: larger potential classes, atoms, or physically realistic charges.
What the AI did
Produced by an unreleased internal OpenAI model as part of OpenAI's openai/math release. The release README says the results used one fixed procedure averaging about three hours of ChatGPT Pro thinking compute per result; this family is not among the README's stated exceptions (the Hodge conjecture for CM abelian varieties and the Re(s) > 11/12 zero-free region). The manuscripts are authored as OpenAI with no human author named.
Verification
No independent mathematician has checked this yet. Checked here: abstract, introduction and Theorem 1.1, read against the representability question as the manuscript frames it from Hohenberg-Kohn, Kohn-Sham, Levy, Lieb and Ullrich-Kohn; proof not refereed. No Lean formalization exists for this family. Scope limits stated by the paper: the counterexample uses nuclear separation in scaled units and a charge given by an exact but non-numerical formula with no effective bound; it excludes only real spin-independent local potentials in , and says nothing about distributional, spin-dependent or nonlocal potentials.
Sources
- CodeOpenAI math release: A Coulomb ground-state density without Kohn-Sham ensemble representation
- Problem recordLieb, Density functionals for Coulomb systems, Int. J. Quantum Chem. 24 (1983)Trushin, Erhard, Gorling, Violations of the v-representability condition underlying Kohn-Sham DFT, PRA 110 (2024)