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arXiv:2512.11476

Bell, Spinors, and the Impossibility of a Classical Spin-Vector Model

G. A. Koroteev

quant-phSubmitted Dec 12, 2025• Announced Dec 15, 2025• 0 citations
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Abstract

We revisit the Bell--CHSH scenario for two spin-\(\tfrac{1}{2}\) particles and isolate the precise algebraic origin of the Bell contradiction. On the quantum side, spin-\(\tfrac{1}{2}\) is described by a noncommutative spinor (Clifford) algebra acting on the Hilbert space of two spin-\(\tfrac{1}{2}\) particles, with the singlet state yielding the usual correlation \(E(a,b) = -\,a\cdot b\) and Tsirelson's bound \(2\sqrt{2}\). On the classical side, the standard Bell assumptions amount to describing all measurement outcomes as \(\{\pm1\}\)-valued random variables on a single Kolmogorov probability space, i.e.\ elements of a commutative algebra \(\mathcal{C}(Λ)\). We show that there is no representation of the spinor algebra of spin-\(\tfrac{1}{2}\) (with its singlet state and locality structure) into any such commutative Kolmogorov algebra that preserves the \(\{\pm1\}\) spectra of local spin components and the singlet correlations entering the CHSH expression, under the standard Bell assumptions of locality (factorization) and measurement independence. In this sense, the Bell--CHSH contradiction is exhibited as an algebraic mismatch between a noncommutative spinor/Clifford description of spin and the classical assumption of a single global Kolmogorov space supporting all outcomes. In the language of quantum probability, this is a C\(^*\)-algebraic reformulation of the known fact that the singlet correlations admit no local hidden-variable model with jointly distributed outcomes on one probability space. We also give an explicit realization of the same spinor structure within the author's Quantum Index Algebra (QIA) framework, where locality appears as disjoint index slots and the singlet state as a simple index cocycle.

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We revisit the Bell--CHSH scenario for two spin-(\tfrac{1}{2}) particles and isolate the precise algebraic origin of the Bell contradiction. On the quantum side, spin-(\tfrac{1}{2}) is described by a noncommutative spinor (Clifford) algebra acting on the Hilbert space of two spin-(\tfrac{1}{2}) particles, with the singlet state yielding the usual correlation (E(a,b) = -,a\cdot b) and Tsirelson's bound (2\sqrt{2}). On the classical side, the standard Bell assumptions amount to describing all measurement outcomes as ({\pm1})-valued random variables on a single Kolmogorov probability space, i.e.\ elements of a commutative algebra (\mathcal{C}(Λ)).
We show that there is no representation of the spinor algebra of spin-(\tfrac{1}{2}) (with its singlet state and locality structure) into any such commutative Kolmogorov algebra that preserves the ({\pm1}) spectra of local spin components and the singlet correlations entering the CHSH expression, under the standard Bell assumptions of locality (factorization) and measurement independence. In this sense, the Bell--CHSH contradiction is exhibited as an algebraic mismatch between a noncommutative spinor/Clifford description of spin and the classical assumption of a single global Kolmogorov space supporting all outcomes. In the language of quantum probability, this is a C(^*)-algebraic reformulation of the known fact that the singlet correlations admit no local hidden-variable model with jointly distributed outcomes on one probability space.
We also give an explicit realization of the same spinor structure within the author's Quantum Index Algebra (QIA) framework, where locality appears as disjoint index slots and the singlet state as a simple index cocycle.
Bell’s theorem is a foundational result in quantum theory, demonstrating that no local hidden-variable model satisfying certain assumptions can reproduce quantum correlations. While mathematically correct within its formal framework, the theorem implicitly relies on a specific representational choice: measurement outcomes are modeled as scalar, commutative variables (±1). This assumption, though natural for flat and static configurations, is not mandated by physical necessity. In this work, we examine the consequences of relaxing this representational constraint when measurement outcomes arise as projections of states with nontrivial topology. We show that when physical correlations are naturally organized as elements of an S³-valued structure — such as those associated with spin and rotational degrees of freedom — the induced measurement algebra becomes noncommutative. Under these conditions, the key algebraic factorizations employed in Bell-type derivations no longer apply. We construct an explicit local, realistic model in which observable correlations reproduce the quantum expectation E(a, b) = − cos θ and violate the CHSH bound S ≤ 2, without invoking non-local interactions or superluminal influences. The effective S³×I structure arises not as a fundamental substrate, but as the natural geometric form taken by the actualization of physical processes within an underlying relational framework. Importantly, this structure was not introduced to address quantum entanglement specifically; it emerged independently in the study of cosmological expansion, emergent gravity, and mass generation. Its relevance to Bell-type correlations follows as a consequence of geometry, not as an ad hoc modification. These results suggest that quantum entanglement may reflect topological features of physical realization rather than intrinsic non-locality. Possible experimental implications and connections to geometric and substrate-based approaches to fundamental physics
This work presents an elegant and conceptually clean geometric bridge between Pauli algebra and the topology of the Hopf fibration. It shows that the well-known Bell singlet correlation E(a, b) = −a·b is not an additional mystery of quantum theory, but is already fully encoded in the standard spinor geometry S³ → S² and in the non-commutative structure of SU(2). The main result can be understood as a representation statement: the Bell correlation admits a natural formulation as the real part of a U(1) holonomy on the Hopf bundle, namely E(a, b) = Re exp(i(π − θ)), where θ is the angle between measurement directions on the Bloch sphere. This holonomy arises from the Berry–Pancharatnam phase defined on the projective space CP¹ ≃ S², and depends only on the associated oriented solid angle. Importantly, this work does not introduce new physical laws and does not modify quantum mechanics. Instead, it demonstrates that the standard result E = −a·b already admits a rigorous geometric interpretation in terms of connections, curvature, and parallel transport. In this sense, the contribution is not a new theory, but a precise geometric reformulation of existing quantum structure. A key clarification concerns interpretation. The non-abelian SU(2) structure appearing here is not a hidden variable in the sense of Bell’s theorem. It describes the geometry of the quantum state space S³, not a set of pre-existing measurement outcomes. The reduction to U(1) reflects the fact that projective measurements access only equivalence classes on S², discarding the global phase. Accordingly, the violation of Bell inequalities arises from non-commutativity of observables, not from hidden parameters or signalling. The value of the work lies in structural unification. It brings together three standard but often separately presented elements: (i) the algebraic form of entangled correlations, (ii) the geometry of spinor space S³ and the Bloch sphere S², and (iii) the holonomy/phase nature of quantum quantities. In this formulation, Bell correlations appear not only as probabilistic objects, but as global geometric features of the underlying state space. This perspective is particularly useful for geometric quantum mechanics, quantum information theory, and pedagogy, where it provides a clear and rigorous insight into the origin of the cosine correlation law. At the same time, the scope is deliberately modest: the construction is fully consistent with standard quantum theory and does not attempt to extend it. The main risk lies in interpretational overreach. While the geometric picture is compelling, it should not be mistaken for an alternative to quantum mechanics or for a hidden-variable completion. Rather, it reveals an internal geometric layer that is already present in the theory. In summary, this work represents a high-quality incremental advance in quantum foundations: not a paradigm shift, but a compact and illuminating reconstruction of a fundamental result in the language of topology and geometry.
Violations of Bell inequalities are commonly interpreted as evidence for nonlocal influences or as constraints on realist descriptions. We show that the failure of Bell-type factorizability arises naturally when observable outcomes are obtained through a non-injective mapping from an underlying configuration space. In this setting, the standard factorization assumption can be viewed as an implicit requirement that observable variables admit a jointly factorizable completion at the underlying level. We demonstrate that this requirement need not hold when the mapping from underlying configurations to observables is many-to-one. The resulting breakdown of probabilistic factorization does not rely on superluminal dynamics or hidden causal influences, but follows from information loss under projection. Observable outcomes correspond to equivalence classes of underlying configurations, preventing the assignment of independent local variables. We illustrate this mechanism with an explicit toy model producing Bell–CHSH violations while preserving operational no-signalling and statistical independence of measurement settings. The model is not intended to reproduce quantum correlations quantitatively, and may exceed the Tsirelson bound; its role is to isolate the structural origin of the violation. This analysis does not contradict Bell’s theorem, but identifies a class of effective descriptions for which its factorizability assumption does not apply. The framework preserves locality at the underlying level, introduces no additional hidden-variable dynamics, and does not modify quantum mechanics. It clarifies how classical factorization is recovered in regimes where the effective mapping becomes approximately injective. In the operator language of quantum theory, the same mechanism admits a natural reformulation in terms of reduction to an effective observable subalgebra by a noncommutative conditional expectation.
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The Bell inequality constrains the outcomes of measurements on pairs of distant entangled particles. The Bell contradiction states that the Bell inequality is inconsistent with the calculated outcomes of these quantum experiments. This contradiction led many to question the underlying assumptions, viz. so-called realism and locality. The probability model underlying the Bell inequality is generally left implicit. We propose an explicit probability model for the CHSH version of the Bell experiment. This model has only two simultaneously observable detector settings per measurement, and therefore does not assume realism. The quantum expectation now becomes a conditional expectation, given the two detector settings. This probability model is in full agreement with both quantum mechanics and experiments. As a result, the model satisfies the Bell inequality; there are no so-called violations. We extend this model to include a hidden variable. This extended model is not Bell-separable. This non-separability implies that the model is non-deterministic or non-local (or both).
Bell’s theorem is widely understood as demonstrating that quantum correlations cannot be explained by any theory of local hidden variables. The experimental violation of Bell inequalities has therefore often been interpreted as evidence for nonlocality or “spooky action at a distance.” This paper proposes a different geometric interpretation. It accepts Bell’s theorem as a decisive refutation of separable preassigned vector realism, but argues that entangled systems need not be modeled as pairs of particles carrying hidden local vector outcomes. Instead, the entangled state is interpreted as a nonseparable bivector coherence relation whose correlated vector outcomes are disclosed only through measurement. On this view, measurement is a basis-conditioned reduction from bivector structure to local vector registration. The standard singlet correlation E(a,b)=-a⋅b, including the Tsirelson bound S=2√2, is then interpreted as the scalar trace of a shared bivector relation rather than as the result of superluminal influence. The framework does not deny Bell’s theorem, Bell experiments, or quantum statistics. It instead reframes their ontological meaning: Bell violation marks the failure of separable vector completion, not the necessity of action at a distance. Keywords: Bell’s theorem; entanglement; bivectors; geometric algebra; spin; nonlocality; measurement; quantum foundations; Tsirelson bound; separable realism; relational ontology; UCCF. Explainer video Watch on YouTube (Roots of Reality): https://youtu.be/wfpY4QZ45ME The video, its thumbnail and description are included in this record.