Violation of Bell inequality with unentangled photons
- Author(s)
- Kai Wang, Zhaohua Hou, Kaiyi Qian, Leizhen Chen, Mario Krenn, Markus Aspelmeyer, Anton Zeilinger, Shining Zhu, Xiao Song Ma
- 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.
- Organisation(s)
- Quantum Optics, Quantum Nanophysics and Quantum Information
- External organisation(s)
- Nanjing University, Max-Planck-Institut für die Physik des Lichts, Eberhard Karls Universität Tübingen, Österreichische Akademie der Wissenschaften (ÖAW), University of Science and Technology of China (USTC)
- Journal
- Science Advances
- Volume
- 11
- No. of pages
- 6
- ISSN
- 2375-2548
- DOI
- https://doi.org/10.48550/arXiv.2507.07756
- Publication date
- 08-2025
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103025 Quantum mechanics, 103021 Optics
- ASJC Scopus subject areas
- General
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/75e775f4-b921-4f18-9885-920c06175907