English

Completing the quantum formalism in a contextually objective framework

Quantum Physics 2022-01-04 v3 History and Philosophy of Physics

Abstract

In standard quantum mechanics (QM), a state vector ψ| \psi \rangle may belong to infinitely many different orthogonal bases, as soon as the dimension NN of the Hilbert space is at least three. On the other hand, a complete physical observable AA (with no degeneracy left) is associated with a NN-dimensional orthogonal basis of eigenvectors. In an idealized case, measuring AA again and again will give repeatedly the same result, with the same eigenvalue. Let us call this repeatable result a modality μ\mu, and the corresponding eigenstate ψ| \psi \rangle. A question is then: does ψ| \psi \rangle give a complete description of μ\mu ? The answer is obviously no, since ψ| \psi \rangle does not specify the full observable AA that allowed us to obtain μ\mu; hence the physical description given by ψ| \psi \rangle is incomplete, as claimed by Einstein, Podolsky and Rosen in their famous article in 1935. Here we want to spell out this provocative statement, and in particular to answer the questions: if ψ| \psi \rangle is an incomplete description of μ\mu, what does it describe ? is it possible to obtain a complete description, maybe algebraic ? Our conclusion is that the incompleteness of standard QM is due to its attempt to describe systems without contexts, whereas both are always required, even if they can be separated outside the measurement periods.

Keywords

Cite

@article{arxiv.2003.03121,
  title  = {Completing the quantum formalism in a contextually objective framework},
  author = {Philippe Grangier},
  journal= {arXiv preprint arXiv:2003.03121},
  year   = {2022}
}

Comments

7 pages, no figure. In v3 first section rewritten in a more pedagogical form, and some additions later on