Nonlocality for two particles without inequalities for almost all entangled states
Abstract
It is shown that it is possible to demonstrate nonlocality for two particles without using inequalities for all entangled states except maximally entangled states such as the singlet state. The eigenvectors corresponding to the measurements that must be performed to do this are exhibited and found to have a particularly simple relationship to the entangled state.
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Earlier no-go results use assumptions similar to (Q) and (S).
“Theorem 1 may be compared to earlier no-go results, such as7–10,41–43, which also use assumptions similar to (Q) and (S) (although the latter is often implicit).”
From Quantum theory cannot consistently describe the use of itself (2018) · cites this paper as [8]
Hardy's thought experiment provides an alternative way to demonstrate a violation of local realism without inequalities for two spin-half particles or photon polarizations.
“Hardy's thought experiment (Hardy 1993) provides an alternative way to demonstrate a violation of local realism without inequalities for two spin-half particles, or equivalently for polarizations of two photons.”
From Multiphoton entanglement and interferometry (2012) · cites this paper as Hardy 1993
In Hardy's ideal situation, quantum mechanics predicts that approximately 9% of photon pairs give coincidence counts absolutely not allowed by local realism.
“In such a case, in the ideal situation, for a specific set of measurements quantum mechanics predicts that approximately 9% of the pairs of photons must give measurement results in a form of coincidence counts absolutely not allowed by local realism.”
From Multiphoton entanglement and interferometry (2012) · cites this paper as Hardy 1993
In Hardy's thought experiment the two particles are nonmaximally entangled.
“A crucial distinguishing feature in Hardy's thought experiment is that the two particles are nonmaximally entangled.”
From Multiphoton entanglement and interferometry (2012) · cites this paper as Hardy 1993
States with a fixed degree of entanglement ε ≃ 4/3 have been deterministically generated in ion traps.
“States with a fi xed degree of entanglement, ε ≃ 4 / 3, have been deterministically generated in ion traps [17]”
From Nonmaximally Entangled States: Production, Characterization, and Utilization (1999) · cites this paper as [17]
Cites
Bell’s Theorem, Quantum Theory and Conceptions of the Universe
(1989) · doi:10.1007/978-94-017-0849-4 · Cited by 1,632 · see citing works
Source of photons with correlated polarisations and correlated directions
Hardy, L. (1992) · Physics Letters A · doi:10.1016/0375-9601(92)90554-y · Cited by 40 · see citing works
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Multiphoton entanglement and interferometry
Pan, J.-W., Chen, Z.-B., Lu, C.-Y., Weinfurter, H., Zeilinger, A., & Żukowski, M. (2012) · Reviews of Modern Physics · doi:10.1103/revmodphys.84.777 · Cited by 1,410 · see citing works
“For instance, for two-particle states, Hardy (1993) has found situations, where quantum mechanics predicts a specific result to occur sometimes, and local realism predicts the same result never to occur (for an experiment see Boschi et al., 1997).”
BackgroundUltrabright source of polarization-entangled photons
Kwiat, P. G., Waks, E., White, A. G., Appelbaum, I., & Eberhard, P. H. (1999) · Physical Review A · doi:10.1103/physreva.60.r773 · Cited by 1,142 · see citing works
Nonmaximally Entangled States: Production, Characterization, and Utilization
White, A. G., James, D. F. V., Eberhard, P. H., & Kwiat, P. G. (1999) · Physical Review Letters · doi:10.1103/physrevlett.83.3103 · Cited by 511 · see citing works
Quantum theory cannot consistently describe the use of itself
Frauchiger, D., & Renner, R. (2018) · Nature Communications · doi:10.1038/s41467-018-05739-8 · Cited by 333 · see citing works
Beyond Bell's theorem: correlation scenarios
Fritz, T. (2012) · New Journal of Physics · doi:10.1088/1367-2630/14/10/103001 · Cited by 243 · see citing works
A no-go theorem for observer-independent facts
Brukner, Č. (2018) · Entropy · doi:10.3390/e20050350 · Cited by 196 · see citing works
How Quantum Mechanics can consistently describe the use of itself
Lazarovici, D., & Hubert, M. (2019) · Scientific Reports · doi:10.1038/s41598-018-37535-1 · Cited by 113 · see citing works
II Quantum Phenomena in Optical Interferometry
Hariharan, P., & Sanders, B. C. (1996) · Progress in Optics · doi:10.1016/s0079-6638(08)70313-5 · Cited by 36 · see citing works
- Authors
- Hardy, L.
- Venue
- Physical Review Letters
- Publisher
- American Physical Society (APS)
- Published
- 1993-09-13
- Volume
- 71
- Issue
- 11
- Pages
- 1665-1668
- ISSN
- 0031-9007 (ISSN-L)
- OpenAlex
- W2093708734
- Cited by
- 772
- References
- 2
- Citations by year
- 2026: 18 · 2025: 19 · 2024: 33 · 2023: 40 · 2022: 29 · 2021: 34 · 2020: 42 · 2019: 64 · 2018: 30 · 2017: 20 · 2016: 27 · 2015: 31 · 2014: 35 · 2013: 34 · 2012: 25
- FWCI
- 9.09
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Physical Review Letters (publishedVersion)
- PubMed (publishedVersion)
- 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 › Statistical and Nonlinear Physics › Noncommutative and Quantum Gravity Theories
- Keywords
- quantum nonlocality, two-particle entanglement, entangled states, maximally entangled states, singlet state, Bell nonlocality
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