Entangled photons, nonlocality, and Bell inequalities in the undergraduate laboratory
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We use polarization-entangled photon pairs to demonstrate quantum nonlocality in an experiment suitable for advanced undergraduates. The photons are produced by spontaneous parametric downconversion using a violet diode laser and two nonlinear crystals. The polarization state of the photons is tunable. Using an entangled state analogous to that described in the Einstein–Podolsky–Rosen paradox, we demonstrate strong polarization correlations of the entangled photons. Bell’s idea of a hidden variable theory is presented by way of an example and compared to the quantum prediction. A test of the Clauser, Horne, Shimony, and Holt version of the Bell inequality finds S=2.307±0.035, in clear contradiction of hidden variable theories. The experiments described can be performed in an afternoon.
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For any hidden-variable theories and arbitrary angles, the Bell parameter satisfies |S| ≤ 2, equivalent to a visibility of coincidence probability V ≤ 0.71 in both H-V and D-A bases.
“It can be proved that for any HVTs and arbitrary angles, Bell parameter satisfies inequality |S|≤2 which is equivalent to the visibility of coincidence probability V≤0.71 in both H-V and D-A basis [54], [76], [77].”
From Nonlocal realism tests and quantum state tomography in Sagnac-based type-II polarization-entanglement SPDC-source (2021) · cites this paper as [54]
Section VIII (p. 6) states that the CHSH inequality holds for hidden-variable theories at arbitrary polarizer angles, and Section IX (p. 6) uses |S| > 2 as the violation threshold. The passages do not state that this is equivalent to a coincidence-probability visibility V ≤ 0.71 in both the H–V and D–A bases. (LLM, conf=0.86)
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Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?
Einstein, A., Podolsky, B., & Rosen, N. (1935) · Physical Review · doi:10.1103/physrev.47.777 · Cited by 16,654 · see citing works
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Motazedifard, A., Madani, S. A., Dashkasan, J. J., & Vayaghan, N. S. (2021) · Heliyon · doi:10.1016/j.heliyon.2021.e07384 · Cited by 16 · see citing works
Transformation of Bell states using linear optics
Mishra, S., & Singh, R. P. (2024) · Physics Open · doi:10.1016/j.physo.2023.100199 · Cited by 8 · see citing works
- Authors
- Dehlinger, D., & Mitchell, M. W.
- Affiliations
- Reed College (US)
- Venue
- American Journal of Physics
- Published
- 2002-08-13
- Volume
- 70
- Issue
- 9
- Pages
- 903-910
- ISSN
- 0002-9505 (ISSN-L)
- 1943-2909
- OpenAlex
- W1968117339
- Cited by
- 137
- References
- 1
- Citations by year
- 2026: 7 · 2025: 10 · 2024: 16 · 2023: 10 · 2022: 6 · 2021: 10 · 2020: 7 · 2019: 10 · 2018: 6 · 2017: 5 · 2016: 8 · 2015: 5 · 2014: 6 · 2013: 2 · 2012: 6
- FWCI
- 1.34
- Type
- journal article
- Language
- en
- Open access
- green
- arxiv.org
- Locations
- American Journal of Physics (publishedVersion)
- arXiv (Cornell University) (submittedVersion)
- arXiv (Cornell University)
- Topics
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Applications
- Physical Sciences › Computer Science › Artificial Intelligence › Quantum Information and Cryptography
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum optics and atomic interactions
- Keywords
- entangled photons, quantum nonlocality, Bell inequalities, polarization entanglement, spontaneous parametric down-conversion, EPR paradox, hidden variable theories, CHSH inequality, polarization correlation, undergraduate physics laboratory
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