Is the Wavefunction Real?

  • W. G. Unruh
Part of the NATO ASI Series book series (ASIC, volume 427)


Using a simple version of the model for the quantum measurement of a two level system, the contention of Aharonov, Anandan, and Vaidman that one must in certain circumstances give the wavefunction an ontological as well as an epistemological significance is examined. I decide that their argument that the wave function of a system can be measured on a single system fails to establish the key point and that what they demonstrate is the ontological significance of certain operators in the theory, with the wave function playing its usual epistemological role.


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  1. [1]
    Y.Aharonov, J. Anandan, L. Vaidman Phys Rev A 47 4616(1993)ADSCrossRefGoogle Scholar
  2. [2]
    See for example the treatment of the Stern Gerlach experiment in D. Bohm Quantum Mechanics p593jff (Prentice Hall, Englewood Cliffs, N.J.)(1951) although he unnecessarily restricts the gradient in the field to lie in the same direction as the field itself. (For a discussion of the relation between the direction of polarisation actually measured in the Stern Gerlach experiment see M. Bloom, K. Erdman, Can J Phys 40, 179(1962))Google Scholar

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© Springer Science+Business Media Dordrecht 1994

Authors and Affiliations

  • W. G. Unruh
    • 1
  1. 1.CIAR Cosmology Program, Dept. of PhysicsUniversity of B. C.VancouverCanada

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