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Four-qubit entanglement from string theory

  1. Sep 3, 2010 #1

    bcrowell

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    "Four-qubit entanglement from string theory"

    This paper

    Borsten et al., "Four-qubit entanglement from string theory," http://arxiv.org/abs/1005.4915 (published in PRL)

    is being described

    http://www.sciencedaily.com/releases/2010/09/100901091938.htm

    in the popular press as a proposal for an experimental test of string theory. Unfortunately I'm not technically adept enough to understand much of the paper. Is this an accurate description, or is the paper really just finding a mathematical equivalence between two theories, one of which describes testable physics and one of which describes Planck-scale physics that we can't test experimentally?

    Since string theory isn't really a theory yet, I'm also not clear on how we can talk about testing it. Is this a case where all versions of string theory make certain generic predictions, so it doesn't matter which version of string theory we're talking about?

    Suppose the four-qubit entanglement experiment is carried out, and the results are not as predicted by this theory that's mathematically equivalent to string theory. Does that mean string theory is wrong? I.e., does this really expose string theory to the risk of being falsified?
     
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  3. Sep 3, 2010 #2

    marcus

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    Re: "Four-qubit entanglement from string theory"

    We already have a thread about that May paper (1005.4915) and the ensuing press releases. I'll get the link.

    Yeah, here is the earlier thread:
    https://www.physicsforums.com/showthread.php?t=425922

    It was started by Kevin_Axion on 1 September.

    I posted this response:


     
    Last edited: Sep 3, 2010
  4. Sep 3, 2010 #3

    marcus

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    Re: "Four-qubit entanglement from string theory"

    The direct answer to the question you raised seems to be:

    No, it is not a test of string theory as a theory of nature, but rather an application of stringy math to something else (quantum information theory).

    It does not offer the prospect of testing the string framework and invalidating it as an approach to describing fundamental physics if some experimental result is not observed.

    The Imperial College PR headline originally said "test" and that was picked up by several other media---leading to some confusion. But then Imperial PR changed the headline so it no longer says that.
     
  5. Sep 21, 2010 #4
    Re: "Four-qubit entanglement from string theory"

    This is why my "science" education is bad, those guys were my lecturers
     
  6. Sep 21, 2010 #5
    Re: "Four-qubit entanglement from string theory"

    Minor miscommunication, it happens, not even scientists are perfect.
     
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