Simple explanation of apparent Bell nonlocality of unentangled photons

• URL: http://arxiv.org/abs/2509.03127v1
• Date: Wed, 03 Sep 2025 08:27:20 GMT
• Title: Simple explanation of apparent Bell nonlocality of unentangled photons
• Authors: Antoni Wójcik, Jan Wójcik,
• Abstract summary: Wang et al. recently reported an experiment that they interpret as demonstrating a violation of Bell's inequality using unentangled photons.<n>We argue that the reported violation does not demonstrate nonlocality without entanglement, but rather reflects a misinterpretation of otherwise valid and interesting multiphoton interference effects.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Wang et al. [Science Advances, 1 Aug 2025 Vol 11, Issue 31] recently reported an experiment that they interpret as demonstrating a violation of Bell's inequality using unentangled photons. Such a claim is highly controversial, since it is well established that product states cannot surpass the bounds set by local hidden variable models. In this manuscript, we analyze the essential features of the experiment through simplified, idealized scenarios. Our analysis shows that the apparent violation of Bell's inequality originates from two key elements: postselection and an unconventional normalization procedure. These steps produce quantities that formally mimic Bell-type correlations but lack the operational meaning required in a genuine Bell test. We therefore argue that the reported violation does not demonstrate nonlocality without entanglement, but rather reflects a misinterpretation of otherwise valid and interesting multiphoton interference effects.

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