# Spin-path entanglement in single-neutron interferometer experiments

## Abstract

There are two powerful arguments against the possibility of extending quantum mechanics (QM) into a more fundamental theory yielding a deterministic description of nature. One is the experimental violation of Bell inequalities, which discards local hidden-variable theories as a possible extension to QM. The other is the Kochen-Specker (KS) theorem, which stresses the incompatibility of QM with a larger class of hidden-variable theories, known as noncontextual hidden-variable theories. We performed experiments with neutron interferometer, which exploits spin-path entanglements in single neutrons. A Bell-like state is generated to demonstrate a violation of the Bell-like inequality and phenomena in accordance with KS theorem: both experiments study quantum contextuality and show clear evidence of the incompatibility of noncontextual hidden variable theories with QM. The value S = 2.202{+-}0.007 Neither-Less-Than-Nor-Equal-To 2 is obtained in the new measurement of the Bell-like inequality, which shows a larger violation than the previous measurement. For the study of KS theorem, the obtained violation 2.291{+-}0.008 Neither-Less-Than-Nor-Equal-To 1 clearly shows that quantum mechanical predictions cannot be reproduced by noncontextual hidden variable theories.

- Authors:

- Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Wien (Austria)

- Publication Date:

- OSTI Identifier:
- 21611644

- Resource Type:
- Journal Article

- Journal Name:
- AIP Conference Proceedings

- Additional Journal Information:
- Journal Volume: 1384; Journal Issue: 1; Conference: S. N. Bose National Centre for Basic Sciences silver jubilee symposium: 75 Years of quantum entanglement: foundations and information theoretic applications, Kolkata (India), 6-10 Jan 2011; Other Information: DOI: 10.1063/1.3635865; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BELL THEOREM; HIDDEN VARIABLES; INTERFERENCE; INTERFEROMETERS; NEUTRONS; QUANTUM ENTANGLEMENT; QUANTUM MECHANICS; SPIN; ANGULAR MOMENTUM; BARYONS; ELEMENTARY PARTICLES; FERMIONS; HADRONS; MEASURING INSTRUMENTS; MECHANICS; NUCLEONS; PARTICLE PROPERTIES

### Citation Formats

```
Hasegawa, Yuji, and Erdoesi, Daniel.
```*Spin-path entanglement in single-neutron interferometer experiments*. United States: N. p., 2011.
Web. doi:10.1063/1.3635865.

```
Hasegawa, Yuji, & Erdoesi, Daniel.
```*Spin-path entanglement in single-neutron interferometer experiments*. United States. doi:10.1063/1.3635865.

```
Hasegawa, Yuji, and Erdoesi, Daniel. Fri .
"Spin-path entanglement in single-neutron interferometer experiments". United States. doi:10.1063/1.3635865.
```

```
@article{osti_21611644,
```

title = {Spin-path entanglement in single-neutron interferometer experiments},

author = {Hasegawa, Yuji and Erdoesi, Daniel},

abstractNote = {There are two powerful arguments against the possibility of extending quantum mechanics (QM) into a more fundamental theory yielding a deterministic description of nature. One is the experimental violation of Bell inequalities, which discards local hidden-variable theories as a possible extension to QM. The other is the Kochen-Specker (KS) theorem, which stresses the incompatibility of QM with a larger class of hidden-variable theories, known as noncontextual hidden-variable theories. We performed experiments with neutron interferometer, which exploits spin-path entanglements in single neutrons. A Bell-like state is generated to demonstrate a violation of the Bell-like inequality and phenomena in accordance with KS theorem: both experiments study quantum contextuality and show clear evidence of the incompatibility of noncontextual hidden variable theories with QM. The value S = 2.202{+-}0.007 Neither-Less-Than-Nor-Equal-To 2 is obtained in the new measurement of the Bell-like inequality, which shows a larger violation than the previous measurement. For the study of KS theorem, the obtained violation 2.291{+-}0.008 Neither-Less-Than-Nor-Equal-To 1 clearly shows that quantum mechanical predictions cannot be reproduced by noncontextual hidden variable theories.},

doi = {10.1063/1.3635865},

journal = {AIP Conference Proceedings},

issn = {0094-243X},

number = 1,

volume = 1384,

place = {United States},

year = {2011},

month = {9}

}