Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields

Observability of 2π rotations: A proposed experiment

A. G. Klein, G. I. Opat

Published Feb 1, 1975• 31 citations
Publisher

Abstract

Rotations by $2\ensuremath{\pi}$ radians of spin-\textonehalf{} systems are predicted to give rise to factors of -1 in the wave function. We propose an experiment involving Fresnel diffraction of thermal neutrons to test this proposition.

DOI
10.1103/physrevd.11.523

Related papers

Observation of 2π Rotations by Fresnel Diffraction of Neutrons

A. G. Klein, G. I. Opat

We report on the first observation of Fresnel diffraction of a beam of unpolarized slow neutrons by individual ferromagnetic domain boundaries. The observed occurrence of destructive interference in the experiment demonstrates that the phase of a spinor wave function changes by a factor of - 1 when the particle described by that wave function is rotated by an odd multiple of $2\ensuremath{\pi}$ radians.

Physical Review Letters•Aug 2, 1976•104 citations

Observation of 4π-symmetry of the neutron wave function under space rotation

F. Mezei, A. Ioffe, Peter Fischer +2 more

Physica B Condensed Matter•Mar 1, 2000•1 citation

4π-symmetry of the neutron wave function under space rotation

A. Ioffe, F. Mezei

Physica B Condensed Matter•Mar 1, 2001•5 citations

Fermionic and bosonic interference during spin rotation through 2π radians

Herbert Joseph Bernstein

Nature•May 1, 1985•6 citations

Spin Precession During Interferometry of Fermions and the Phase Factor Associated with Rotations Through 2π Radians

Herbert Joseph Bernstein

A proposed experiment which combines spin precession and two-slit interferometry of unpolarized neutrons is analyzed. The analysis elucidates the connection with a possible observation of the phase factor (-1) associated with the rotation of a half-integral spin particle through $2\ensuremath{\pi}$ radians.

Physical Review Letters•Jun 12, 1967•89 citations

Critical Remark on the Observability of the Sign Change of Spinors under 2π Rotations

Gerhard C. Hegerfeldt, K. Kraus

In a recent paper, Aharonov and Susskind claimed rotations by 2π to have observable effects on spinors. Their reasoning is shown to be inconclusive.Received 21 September 1967DOI:https://doi.org/10.1103/PhysRev.170.1185©1968 American Physical Society

Physical Review•Jun 25, 1968•17 citations
Rotations by 2\ensuremathπ2\ensuremath{\pi}2\ensuremathπ radians of spin-\textonehalf{} systems are predicted to give rise to factors of -1 in the wave function. We propose an experiment involving Fresnel diffraction of thermal neutrons to test this proposition.