Violation of Bell inequality with unentangled photons

2025/07/10 by Kai Wang, Wang, Kai, Zhaohua Hou +16 · 4 voices · 7 citations
Computer Science · Medicine · Physics and Astronomy · #Bell state #Bell test experiments #Bell's theorem #Biofield Effects and Biophysics #Counterintuitive #Local hidden variable theory #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum correlation #Quantum discord #Quantum entanglement #Quantum mechanics #Quantum network #Quantum nonlocality #Quantum teleportation #Theoretical physics

paper · pdf · doi:10.1126/sciadv.adr1794

published in Science Advances 11(31), eadr1794 (American Association for the Advancement of Science)

openalex publication_date 2025/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Violation of local realism via Bell inequality-a profound and counterintuitive manifestation of quantum theory that conflicts with the prediction of local realism-is viewed to be intimately linked with quantum entanglement. Experimental demonstrations of such a phenomenon using quantum entangled states are among the landmark experiments of modern physics and paved the way for quantum technology. Here, we report the violation of the Bell inequality that cannot be described by quantum entanglement in the system but arises from quantum indistinguishability by path identity, shown by the multiphoton frustrated interference. By analyzing the measurement of four-photon frustrated interference within the standard Bell-test formalism, we find a violation of Bell inequality by more than four SDs. Our work establishes a connection between quantum correlation and quantum indistinguishability, providing insights into the fundamental origin of the counterintuitive characteristics observed in quantum physics.

Citations

• Die gegenw�rtige Situation in der Quantenmechanik
• Gaussian quantum information
• Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?

Cited by

• Quantum nonlocal correlations of anomalous weak values
• Bell Inequality Violations Without Entanglement? It's Just Postselection
• Analytical Fock Representation of Two-Mode Squeezing for Quantum Interference
• Automated Discovery of Non-local Photonic Gates
• Unquestionable Bell theorem for interwoven frustrated down conversion processes
• From Wavefunctional Entanglement to Entangled Wavefunctional Degrees of Freedom
• Vectorial probability loophole in Bell test
• Quantum Correlations in Classical Systems
• On the quantum separability of qubit registers

Discussions

• Violation of Bell's inequality without entanglement. This looks like fascinating work: apparently the inequality can also be violated when quantum particles are simply indistinguishable. www.arxiv.org [bsky, 32 points, 4 comments]
• #arXiv Violation of Bell Inequality with Unentangled Photons https://arxiv.org/abs/2507.07756 #Bullshit “fake a violation of a Bell inequality via post-selection, via detection efficiency,” shown by M [bsky, 5 points, 0 comments]
• Violation of Bell inequality with unentangled photons [hn, 2 points, 0 comments]
• # arXiv Violation of Bell Inequality with Unentangled Photons https:// arxiv.org/abs/2507.07756 # Bullshit “fake a violation of a Bell inequality via post-selection, via detection efficiency” as shown [mastodon, 0 points, 0 comments]

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• Significant-loophole-free test of Bell's theorem with entangled photons
• On Quantum Entanglement and Nonlocality