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## Main Question or Discussion Point

**"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?