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Quantum Reports

Experimental Proof That Bell’s Inequality Cannot Falsify Local Realism, Together with Corresponding Cause Analysis and Conjectures

Ting Zhou

Published Apr 25, 2026• 0 citations
Publisher

Abstract

Conventional tests of Bell’s inequality rely on entangled photon pairs. Here, we replace entangled pairs with two independent photons of orthogonal polarization, and demonstrate that Bell’s inequality is still violated. Given the inherent local realism of independent photons, this experiment proves that Bell’s inequality cannot falsify the local realism of photons. We thus conjecture that the violation of Bell’s inequality by entangled photon pairs originates from their orthogonal polarizations, rather than the breakdown of local realism. To interpret this unexpected violation with independent photons, we further substitute the two photons with two monochromatic light beams, and calculate the transmittance correlation through polarizers via Malus’s law and Karl Pearson’s correlation formula. We show that this correlation also defies Bell’s inequality. Retracing the derivation of Bell’s inequality reveals its validity is restricted to binary events, which accounts for the observed violation with light beams. Finally, we propose a thought experiment involving gradual attenuation of light intensity down to the single-photon regime, and hypothesize that single-photon transmission through a polarizer does not constitute a binary event. This hypothesis provides a unified interpretation for both our experimental findings and all canonical Bell inequality tests reported to date.

DOI
10.3390/quantum8020039

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Bell inequality experiments have demonstrated that quantum entanglement violates the predictions of local realism. However, all Bell experiments are based on joint measurements of two photons, and their analysis implicitly assumes that "the polarization state of a single photon is ideally linear." This paper proposes an experimental scheme to directly test this assumption: using type-II spontaneous parametric down-conversion (SPDC) to generate polarization-entangled photon pairs, employing fixed-angle measurement of the e-light channel as a coincidence gate to filter entangled photons in the o-light channel, then scanning the o-light analyzer angle with high precision to measure the coincidence count rate as a function of the analyzer angle, testing whether it strictly follows Malus' law I(\theta)=I_0\cos^2(\theta-\theta_0). If systematic deviation is observed in the curve, it would indicate the existence of asymmetric secondary polarization structures in the polarization state of entangled photons, providing an alternative explanatory pathway for Bell inequality violation distinct from nonlocality. This experiment employs a high-precision coincidence measurement scheme to ensure statistical significance and designs multiple control experiments to eliminate systematic errors. The experiment can be implemented in laboratories equipped with standard quantum optics equipment.
ABSTRACT This work presents a revised analysis and corresponding perspective of Bell‐type inequalities and their connection to entanglement in polarization experiments with single‐photon resolution. It is argued that standard derivations of Bell‐type inequalities implicitly rely on additional assumptions beyond those originally stated, specifically concerning the cardinalities of the sets of measurements and the sets of photon‐pair properties (Einstein's elements of physical reality, Bell's ). Any model‐based averages must depend on these cardinalities and violations of Bell‐type inequalities become possible for certain ranges of them. In addition, we argue that for Aspect‐type experiments, the statistical properties associated with Bell's (hidden variable) λ can be different before and after actual photon‐transmission through the polarizers. This distinction is particularly necessary for the actual equipment used in the Aspect‐type experiments. Building on these observations, we construct a model based on a consistent evaluation of the measurement events relative to each other. The model reproduces all quantum‐mechanical expectation values for polarization correlations without invoking instantaneous influences at a distance, and additionally yields explicit outcomes for individual photon‐pair measurements. Within this framework, our Einstein‐type Global Space‐Time Model (GSTM) accounts also for polarization correlations in Malus‐type experiments and addresses all commonly discussed paradoxes associated with single‐photon measurements.