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arXiv · 2502.13846

Violation of Bell inequalities from Cosmic Microwave Background data

Roberto Dale·Jesús M. Gandía·Juan Antonio Morales-Lladosa·Ramon Lapiedra
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Abstract

In a recent paper [R. Dale. R. Lapiedra, and J. A. Morales-Lladosa, Phys. Rev. D {\bf 107}, 023506 (2023)] a cosmic-like Clauser-Horne-Shimony-Holt (CHSH) inequality was proved for the temperature fluctuations $δT$ of the perturbed Cosmic Microwave Background (CMB), assuming local realism. This inequality can be tested from observational data. In fact, no violation for it has been found from the CMB data provided by the COBE satellite in different sky directions. This is a result which, being negative, is not conclusive in relation to the possible violation of the CHSH inequality in a cosmological context. So, the preceding analysis needs to be extended by using more precise current CMB data, like those provided by WMAP and Planck satellites. This is a task of considerable importance but, technically, much more involved in data treatments. In this work, assuming again local realism behind measurements and observational data, this extension is accomplished. The result is that a sound violation of the CHSH inequality is found, which would mean the failure of the assumed local realism in accordance with the quantum origin of the primordial temperature fluctuations in the framework of standard inflation and the orthodox interpretation of the Quantum Mechanics.

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Roberto Dale, Jesús M. Gandía, Juan Antonio Morales-Lladosa, Ramon Lapiedra. 2025-09-04. Violation of Bell inequalities from Cosmic Microwave Background data. https://doi.org/10.1088/1475-7516%2F2025%2F07%2F044

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