Entanglement and the Pauli exclusion priciple


In this context it is convenient to look at entanglement as a resource for quantum information tasks. There are several opinions about usefulness of correlations between identical particles as such a resource, but I think the most orthodox one is expressed in this review: http://arxiv.org/abs/1312.4311. The main point follows already from the title: you can extract entanglement from such correlations, but you can't use it otherwise, which means that there is no entanglement.


Related videos on Youtube

Z Leach
Author by

Z Leach

I'm a senior university student trying to make it through my last few classes to get my BS in Physics.

Updated on August 01, 2022


  • Z Leach
    Z Leach over 1 year

    Could you say that two electrons in the ground state of a helium atom experience quantum entanglement? They are both in the same energy level and cannot have the same quantum numbers. If one is spin up, the other must be spin down. So, if one "flipped" spins, the other would have to also flip spins or violate sassy Pauli exclusion principle.

    • march
      march almost 8 years
      I've never seen the Pauli exclusion principle described as "sassy"! But in any case, I would say yes: the electrons in any atom are (in some sense trivially) entangled because you have to anti-symmetrize the many-electron wave function, and such a state cannot be a product state.
    • Norbert Schuch
      Norbert Schuch almost 8 years
      Entanglement arising from (anti-)symmetrization is a subtle issue and it depends very much on the perspective (i.e., what you call entanglement), see also the answer by Nicolai Miklin.
  • Z Leach
    Z Leach almost 8 years
    So you mean they are entangled in a way, but not in the useful way that people are interested in? Does that sum up what you mean?
  • Nikolai Miklin
    Nikolai Miklin almost 8 years
    Yes. Pretty much. Although some people (maybe most of them) prefer not to call it entanglement, it is tricky, because these correlations look like entanglement.
  • Lewis Miller
    Lewis Miller almost 8 years
    They are indeed entanglement, just not of a sort useful for QIT
  • Rococo
    Rococo over 6 years
    Am I missing something stupid or does the cited paper say literally the opposite of what is being claimed in this answer? From the abstract: "we show that any entanglement formally appearing amongst the identical particles, including entanglement due purely to symmetrization, can be extracted into an entangled state of independent modes, which can then be applied to any task." Which seems to be clearly claiming that identical particle entanglement is a full resource for quantum information and in that sense should be considered "true" entanglement.
  • Rococo
    Rococo over 6 years