We present a constraint-based axiomatization of quantum correla- tions that derives Bell statistics without invoking Hilbert space, wave functions, or causal mechanisms. Starting from five physically moti- vated axioms—rotational invariance, perfect anti-correlation, uniform marginals (no-signaling), smoothness, and extremality—we prove that the singlet correlation function E(ˆ a,ˆˆb) =−ˆa·b is uniquely deter- mined. The proof proceeds through functional equation analysis: the extremality axiom implies angle additivity, reducing the problem to Cauchy’s equation with boundary conditions. We derive the Tsirelson bound |S|≤2√2 directly from this correlation function without op- erator algebras, and show that CHSH violation follows as a theorem. The no-signaling condition emerges as a structural property of the con- straint, ensuring compatibility with relativistic causality. We extend the framework to tripartite systems, deriving GHZ correlations from analogous axioms and proving maximal Mermin inequality violation. The constraint interpretation dissolves the tension between entangle- ment and causality: correlations are neither caused nor explained by hidden variables—they are specified by the constraint structure itself. This framework recovers all quantum predictions while eliminating causation from the foundational ontology.
We present a constraint-based axiomatization of quantum correla- tions that derives Bell statistics without invoking Hilbert space, wave functions, or causal mechanisms. Starting from five physically moti- vated axioms—rotational invariance, perfect anti-correlation, uniform marginals (no-signaling), smoothness, and extremality—we prove that the singlet correlation function E(ˆ a,ˆˆb) =−ˆa·b is uniquely deter- mined. The proof proceeds through functional equation analysis: the extremality axiom implies angle additivity, reducing the problem to Cauchy’s equation with boundary conditions. We derive the Tsirelson bound |S|≤2√2 directly from this correlation function without op- erator algebras, and show that CHSH violation follows as a theorem. The no-signaling condition emerges as a structural property of the con- straint, ensuring compatibility with relativistic causality. We extend the framework to tripartite systems, deriving GHZ correlations from analogous axioms and proving maximal Mermin inequality violation. The constraint interpretation dissolves the tension between entangle- ment and causality: correlations are neither caused nor explained by hidden variables—they are specified by the constraint structure itself. This framework recovers all quantum predictions while eliminating causation from the foundational ontology.
We propose that causation does not exist in the physical worldbut explanationdoes. Our framework distinguishes two structures often conated: derivation (the-orems follow from axioms) and causation (events produce other events). Physicsretains the former while eliminating the latter. Beginning from constraint axiomsempirically discovered structures that cannot themselves be derivedwe show thatapparent causal claims become theorems: synchronization, phase transitions, andmeasurement outcomes are derivable from constraint geometry, not produced bycausal mechanisms. The quantum measurement problem dissolves because col-lapse presupposes causation; what remains is constraint satisfaction. Entanglementis correlation constraint, not action at a distance. Spacetime emerges as a perspec-tival feature of embedding within atemporal constraint structure. We situate thisframework relative to Adlam's constraint-based laws, Rovelli's relational quantummechanics, and ontic structural realism. The methodological principle is: axiomscannot be causally explained (this would require prior causes), but theorems can bederived from them. Explanation terminates not in deeper causes but in empiricallydiscovered constraint structures.
The tension between quantum entanglement and relativistic causality has persisted fornearly a century. Bell inequality violations demonstrate correlations inexplicable by localhidden variables, yet relativity prohibits faster-than-light causal inuences. We dissolvethis tension through causal eliminativism: causation does not exist in fundamental physics.Three results follow: (1) Bell correlations are derivable as atemporal relational constraintswithout causation; (2) relativity prohibits superluminal causation, which does not exist,not superluminal correlation, which does; (3) the measurement problem disappears whenreconceived as constraint activation rather than causal collapse. The 90-year problem wasan artifact of imposing causal categories onto an acausal world. We survey the neo-Russelliantradition supporting this move, address the measurement problem's standard formulation(Maudlin 1995), and demonstrate concrete applications to the Wigner's friend scenario andBell's theorem premises.
Bell inequalities characterize the boundary of the local-realist correlation polytope -- the set of joint probability distributions achievable by classical hidden-variable models. Quantum mechanics exceeds this boundary through non-commutativity, reaching the Tsirelson bound 22 for CHSH. We show that this polytope structure is not specific to quantum foundations: it appears identically in the causal inference literature, where the instrumental inequality, the Balke--Pearl linear programming bounds, and the Tian--Pearl probabilities of causation all arise as facets of the same marginal compatibility polytope. Fine's theorem -- that CHSH inequalities hold if and only if a joint distribution exists -- is precisely the pivot: the instrumental variable model in causal inference is structurally equivalent to the Bell local hidden-variable model, with the instrument playing the role of the measurement setting and the latent confounder playing the role of the hidden variable λ. We develop this correspondence in detail, extending it to algorithmic (Kolmogorov complexity) and entropic formulations of Bell inequalities, the NPA semidefinite programming hierarchy, and the MIP∗=RE undecidability result. We further show that the Born-rule / Bayes-rule duality underlying quantum Bayesian computation exploits the same non-commutativity that enables Bell violation, providing polynomial speedups for posterior inference. The framework yields a concrete dictionary between quantum information theory, causal econometrics, and Bayesian computation, and suggests new directions including NPA-based quantum causal inference algorithms and quantum architectures for function approximation.
Bell's theorem asserts that no local hidden variable theory can explain the predictions of quantum theory in an experiment where spacelike separated measurements are performed in distant laboratories. Loophole-free Bell tests performed in the last decade demonstrate Bell nonlocality as a property of Nature. However, the amount of nonlocality allowed in quantum theory is limited, compared to the sole restriction of no-signaling, meaning the impossibility of faster-than-light communication implied by special relativity. Information causality is a physical principle that generalizes no-signaling and is satisfied by quantum theory. It is based on the idea that shared quantum entanglement cannot enable a receiver to obtain more classical information than how much was sent by a distant sender. Remarkably, the principle was shown to imply the maximal quantum bound for the violation of the most well-known Bell inequality. The aim of this thesis is to widen our understanding of information causality and compare its predictions with other known outer approximations of the quantum set of correlations. We build upon the recent realization that most of the known consequences of information causality can be derived with a single copy of the shared systems, whereas before it was thought that many copies were necessary. We develop a novel optimization framework which bounds the possible violations of information causality by other sets of correlations, allowing us to certify when violations are not possible. We generalize the statement of information causality and reach a precise definition for the set of correlations satisfying this principle. We show that when searching for violations of information causality by physical theories, considering many copies is not necessary. Our aforementioned optimization framework approximates the information causality set from the outside. Conversely, we propose a different approach which allows us to approximate this set from the inside.
In 1964, John Bell showed that any local hidden‑variable theory must satisfy a specific inequality on correlations between distant measurements. In its CHSH form (Clauser, Horne, Shimony, Holt 1969), the inequality reads |S| = |E(a,b) + E(a,b′) + E(a′,b) − E(a′,b′)| ≤ 2, where E(a,b) is the correlation between measurement outcomes at two separated parties using settings a and b. Any local realist theory respects this bound. Quantum mechanics violates it. Experiments confirm the violation. The standard quantum prediction for a maximally entangled state with optimal measurement angles is |S| = 2√2 ≈ 2.828. In 1980, Boris Tsirelson proved that 2√2 is not just one quantum prediction — it is the *maximum* value any quantum correlation can produce. No quantum state, no measurement scheme, no clever protocol can push |S| beyond 2√2. The bound is sharp, the value is exact, and it has been measured in laboratories around the world to experimental precision. The Tsirelson bound is one of the deepest empirical structures in physics. It tells us that quantum correlations exceed classical correlations by a specific, finite amount — there is room to violate Bell’s inequality, but only so much room. The number 2√2 has no obvious physical interpretation. It does not appear in the formulation of quantum mechanics. It emerges from the mathematics of the bipartite Hilbert space when the CHSH operator is constructed and bounded. The question is where it comes from. In standard QM, the answer is that it falls out of the Hilbert‑space structure plus Cauchy–Schwarz plus an operator‑norm bound on the CHSH operator. Technically correct, and Tsirelson’s 1980 proof remains the canonical derivation — but it leaves the deeper structure unanswered. The Hilbert space is postulated. The inner product that makes Cauchy–Schwarz available is postulated. The bipartite tensor‑product structure on H_A ⊗ H_B is postulated. The 2√2 value is what those postulates produce when run through the CHSH operator. This walkthrough shows how the Event Density framework derives the Tsirelson bound from a smaller set of structural commitments. The Hilbert‑space structure, the inner product, and the bipartite tensor‑product structure all emerge as forced consequences of the substrate ontology rather than being postulated. With those structures forced rather than assumed, Tsirelson’s 1980 argument applies directly, and the 2√2 value is no longer the output of a chain of postulates but the output of a chain of derived theorems. Like Heisenberg, Bell–Tsirelson is a place where the framework’s contribution is upstream. The bound itself is mathematical physics already in the literature; what changes is the foundational status of the structures the argument requires. ED does not produce a new derivation step beyond standard QM here — it removes the postulational status of the structures the standard derivation already uses. The 2√2 value is now a derived consequence of the substrate ontology, all the way down.
Bell inequalities are commonly presented as abstract constraints derived from assumptions of locality and realism, while their violation in quantum mechanics is often regarded as a profound mystery. In this work I present an operational reconstruction of Bell correlations using a constraint-based framework in which all assumptions are made explicit and executable. By separating locality, factorization, signaling, contextuality, and nonlocal correlation into independently controllable components, I demonstrate numerically that Bell inequality violation arises if and only if joint probability factorizability is relaxed. Quantum correlations emerge as extremal, geometrically constrained solutions within a broader space of admissible correlations. No appeal is made to wavefunction collapse or Hilbert space axioms. The results clarify the precise content of Bell’s theorem and suggest that quantum nonlocality is best understood as a global consistency constraint rather than a dynamical influence.