International Journal of Theoretical Physics

, Volume 51, Issue 6, pp 1783–1791 | Cite as

Nonlocal Appearance of a Macroscopic Angular Momentum



We discuss a type of measurement in which a macroscopically large angular momentum (spin) is “created” nonlocally by the measurement of just a few atoms from a double Fock state. This procedure apparently leads to a blatant nonconservation of a macroscopic variable—the local angular momentum. We argue that while this gedankenexperiment provides a striking illustration of several counter-intuitive features of quantum mechanics, it does not imply a non-local violation of the conservation of angular momentum.


Nonlocality Quantum measurement Bose-Einstein condensate 


  1. 1.
    Laloë, F.: Bose-Einstein condensates and EPR quantum non-locality. In: Nieuwenhuizen, T.M., et al. (ed.) Beyond the Quantum, pp. 35–52. World Scientific, Singapore (2007). arXiv:0704.0386 CrossRefGoogle Scholar
  2. 2.
    Andrews, M.R., et al.: Observation of interference between two Bose condensates. Science 275, 637–641 (1997) CrossRefGoogle Scholar
  3. 3.
    Javanainen, J., Yoo, S.M.: Quantum phase of a Bose-Einstein condensate with an arbitrary number of atoms. Phys. Rev. Lett. 76, 161–164 (1996) ADSCrossRefGoogle Scholar
  4. 4.
    Castin, Y., Dalibard, J.: Relative phase of two Bose-Einstein condensates. Phys. Rev. A 55, 4330–4337 (1997) ADSCrossRefGoogle Scholar
  5. 5.
    Laloë, F.: The hidden phase of Fock states; quantum non-local effects. Eur. Phys. J. D 33, 87–97 (2005) ADSCrossRefGoogle Scholar
  6. 6.
    Mullin, W.J., Krotkov, R., Laloë, F.: Evolution of additional (hidden) quantum variables in the interference of Bose-Einstein condensates. Phys. Rev. A 74, 023610 (2006) ADSCrossRefGoogle Scholar
  7. 7.
    Mullin, W.J., Krotkov, R., Laloë, F.: The origin of the phase in the interference of Bose-Einstein condensates. Am. J. Phys. 74, 880–887 (2006) ADSCrossRefGoogle Scholar
  8. 8.
    Laloë, F., Mullin, W.J.: Einstein-Podolsky-Rosen argument and Bell inequalities for Bose-Einstein spin condensates. Phys. Rev. A 77, 022108 (2008) ADSCrossRefGoogle Scholar
  9. 9.
    Paraoanu, G.S.: Localization of the relative phase via measurements. J. Low Temp. Phys. 153, 285–293 (2008) ADSCrossRefGoogle Scholar
  10. 10.
    Paraoanu, G.S.: Phase coherence and fragmentation in weakly interacting bosonic gases. Localization of the relative phase via measurements. Phys. Rev. A 77, 041605 (2008) ADSCrossRefGoogle Scholar
  11. 11.
    Einstein, A., Podolsky, B., Rosen, N.: Can quantum-mechanical description of reality be considered complete?. Phys. Rev. 47, 777–780 (1935) ADSMATHCrossRefGoogle Scholar
  12. 12.
    Bohm, D.: Quantum Theory. Prentice-Hall, New York (1951) Google Scholar
  13. 13.
    Greenberger, D.M., Horne, M.A., Zeilinger, A.: In: Kafatos, M. (ed.) Bell’s Theorem, Quantum Theory, and Conceptions of the Universe, pp. 73–76. Kluwer, Dordrecht (1989) Google Scholar
  14. 14.
    Healey, R.: Quantum theory: a pragmatist approach. Br. J. Philos. Sci. (forthcoming). arXiv:1008.3896
  15. 15.
    Peres, A.: Quantum Theory: Concepts and Methods. Kluwer Academic, Dordrecht (1993) MATHGoogle Scholar
  16. 16.
    Leggett, A.J., Sols, F.: On the concept of spontaneously broken gauge symmetry in condensed matter physics. Found. Phys. 21, 353–364 (1991) ADSCrossRefGoogle Scholar

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© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Institute for Quantum Optics and Quantum Information (IQOQI)Austrian Academy of SciencesViennaAustria
  2. 2.Low Temperature LaboratoryAalto UniversityAaltoFinland
  3. 3.Department of PhilosophyUniversity of ArizonaTucsonUSA

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