Letter | Published:

Measurement of a confinement induced neutron phase

Nature volume 417, pages 630632 (06 June 2002) | Download Citation

Subjects

Abstract

Particle physicists see neutrons as tiny massive particles with a confinement radius of about 0.7 fm and a distinct internal quark–gluon structure. In quantum mechanics, neutrons are described by wave packets whose spatial extent may become ten orders of magnitude larger than the confinement radius, and can even reach macroscopic dimensions, depending on the degree of monochromaticity. For neutrons passing through narrow slits, it has been predicted1,2 that quantization of the transverse momentum component changes the longitudinal momentum component, resulting in a phase shift that should be measurable using interferometric methods3. Here we use neutron interferometry to measure the phase shift arising from lateral confinement of a neutron beam passing through a narrow slit system. The phase shift arises mainly from neutrons whose classical trajectories do not touch the walls of the slits. In this respect, the non-locality of quantum physics is apparent.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    A geometrical quantum phase effect. Phys. Lett. A 125, 441–442 (1987)

  2. 2.

    A new non-local effect in quantum mechanics. Physica B 151, 374–377 (1988)

  3. 3.

    & Neutron Interferometry (Clarendon, Oxford, 2000)

  4. 4.

    & Influence of retardation on the London-van der Waals forces. Phys. Rev. 73, 360–372 (1948)

  5. 5.

    & Cavity quantum electrodynamics. Sci. Am. 268, 26–33 (1993)

  6. 6.

    , , & On the quantum foundations of the experimental decay law. Nuovo Cimento A 15, 689–704 (1973)

  7. 7.

    & The Zeno's paradox in quantum theory. J. Math. Phys. 18, 756–763 (1977)

  8. 8.

    et al. Determination of atom-surface van der Waals potentials from transmission diffraction intensities. Phys. Rev. Lett. 83, 1755–1758 (1999)

  9. 9.

    & Deviations from classical optics in matter diffraction and determination of the size of weakly bound molecules. Phys. Rev. A 61, 023606-1–023606-10 (2000)

  10. 10.

    Ferry, D. K., Grubin, H., Jacobini, C. & Jauho, A. J. (eds) Quantum Transport in Ultrasmall Devices (Plenum, New York, 1995)

  11. 11.

    , , , & Channeling atoms in a laser standing wave. Phys. Rev. Lett. 59, 1659–1662 (1987)

  12. 12.

    et al. Adiabatic following in standing-wave diffraction of atoms. Appl. Phys. B 69, 303–309 (1999)

  13. 13.

    , , & Quantum phase shift caused by spatial confinement. Found. Phys. 29, 325–332 (1999)

  14. 14.

    et al. Quantum states of neutrons in the Earth's gravitational field. Nature 415, 297–299 (2002)

  15. 15.

    Practical Quantum Mechanics (Springer, Berlin, 1971)

  16. 16.

    & Quantum phase shift of spatially confined de Broglie waves in a gravitational field. Phys. Lett. A 248, 114–116 (1998)

  17. 17.

    , , , & Measurement and characterization of the three-dimensional coherence function in neutron interferometry. Phys. Rev. A 53, 902–908 (1996)

  18. 18.

    & Neutron interferometer absorption experiments in the quantum limit. Phys. Rev. A 46, 7284–7287 (1992)

Download references

Acknowledgements

This work was supported by the Austrian Science Foundation and a TMR-Network of the European Union EU. Useful discussions with J. Summhammer and D. Petrascheck are gratefully acknowledged.

Author information

Affiliations

  1. *Atominstitut der Österreichischen Universitäten, A-1020 Wien, Austria

    • H. Rauch
    • , H. Lemmel
    • , M. Baron
    •  & R. Loidl
  2. †Institut Laue-Langevin, BP 156, F-38042 Grenoble, France

    • M. Baron
    •  & R. Loidl

Authors

  1. Search for H. Rauch in:

  2. Search for H. Lemmel in:

  3. Search for M. Baron in:

  4. Search for R. Loidl in:

Competing interests

The authors declare that they have no competing financial interests.

Corresponding author

Correspondence to H. Rauch.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature00773

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.