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Research . 2026
License: CC BY
Data sources: Datacite
ZENODO
Research . 2026
License: CC BY
Data sources: Datacite
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Hardy's Paradox and the Fano Associator: A Geometric Diagnosis of Quantum Contextuality

Authors: Buckley, Ian R. C.;

Hardy's Paradox and the Fano Associator: A Geometric Diagnosis of Quantum Contextuality

Abstract

Hardy's paradox is an all-versus-nothing logical contradiction for bipartite quantum systems: three jointly satisfiable conditions on measurement probabilities each force a fourth probability to zero by classical logic, yet quantum mechanics permits that fourth probability to be strictly positive. Unlike Bell inequalities, no statistical averaging is required — the contradiction is exact and logical. This paper presents a five-part numerical study connecting Hardy's paradox to the non-associative geometry of the Fano plane $PG(2,2)$ and the octonion associator $\mathcal{A}(e_i, e_j, e_k) = (e_i e_j)e_k - e_i(e_j e_k)$. Part 1 finds the Hardy state by constrained optimisation (Nelder-Mead, 100 initialisations), confirming all three zero-conditions to within $10^{-6}$ and the impossible event $P(Z^+, Z^+) = 0.10 > 0$ with residual $\sim 10^{-36}$. Part 2 shows that the Fano-SYK ground state restricted to the measurement node pair ${0,1}$ is entangled, with von Neumann entropy $S = 0.8762$ ebits, connecting the Fano dynamical structure to the Hardy contextual structure. Part 3 sweeps a one-parameter entangled state family and demonstrates that the Hardy impossible-event probability and the CHSH witness are correlated (Pearson $r = 0.982$), both vanishing at the separable limit. Part 4 verifies the full octonion associator table: $|\mathcal{A}(e_i,e_j,e_k)| = 0$ for all 7 Fano lines (associative triples) and $|\mathcal{A}| = 2$ for all 28 non-Fano triples, exact to $< 10^{-14}$. Part 5 maps the Hardy measurement settings $Z, X$ to octonion directions $e_0, e_1$, which lie on the unique Fano line ${0,1,3}$, and argues that entanglement forces the bipartite system to sample non-Fano directions in $\mathbb{R}^7 \otimes \mathbb{R}^7$ where no consistent classical truth-value assignment exists. The central claim — stated as the Fano-Contextuality Conjecture — is that a measurement triple admits a consistent joint classical value assignment if and only if the corresponding octonion directions lie on a Fano line ($|\mathcal{A}| = 0$). Hardy contextuality is diagnosed as the consequence of entanglement distributing quantum weight into the non-associative region of measurement space. A formal proof connecting this partition to the Kochen-Specker theorem is identified as the primary open problem. This is the first paper in the ASA Quantum Foundations series (Portfolio F), accompanied by the Spacelike Associator Paradox (doi:10.5281/zenodo.20058013) and the Fano Monogamy Paradox (doi:10.5281/zenodo.20058092). Working paper in the Adelic Simplicial Architecture (ASA) series.

Keywords

Non-Associative Geometry, Bell Inequality, Octonions, CHSH Witness, Fano Plane, Measurement Contextuality, Quantum Foundations, Exact Diagonalisation, Octonion Associator, Hidden Variable Theory, G2 Lie Group, Entanglement, Exceptional Lie Algebra, Quantum Non-Locality, Quantum Contextuality, Fano-SYK Model, Hardy's Paradox, Adelic Simplicial Architecture, All-Versus-Nothing Contradiction, Kochen-Specker Theorem

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
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