For the $|W_3\rangle=\frac{1}{\sqrt{3}}(|001\rangle+|010\rangle+|100\rangle)$, what does W stand for? Does it refer to an author name? Anyone knows a reference? Thanks


1 Answer 1


Apparently $\vert W \rangle$ was first reported (and the naming convention first adopted) by Dür, Vidal and Cirac in this preprint on May 26, 2000 (version 1 of 2).

This is supported by the footnote on page 4 of this preprint on June 25, 2000 (version 3 of 3, this footnote did not appear in the earlier versions), which states (in part)

Very recently Dürr [sic], Vidal, and Cirac (LANL eprint quantph/0005115) have found a tripartite pure state of 3 qubits which is stochastically incomparable with the GHZ state.

Dür, Vidal and Cirac don't explicitly ascribe any special significance to the notational choice $\vert W \rangle$, so it seems that only the authors could say with any confidence whether $W$ has any significance.

Edit: The lead author's first initial is W. (for Wolfgang), which is plausible motivation for the notation $\vert W \rangle$, but I'm not aware of any evidence to support this.

  • 3
    $\begingroup$ I, for one, really appreciate the lack of DVC notation - I struggle enough with GHZ, trying to misspell it as GHC or something else about half of the time :-) $\endgroup$ Commented Oct 21, 2019 at 2:01
  • $\begingroup$ Thanks for the answer. I did search DVC paper and could not find an explanation. I will wait to see if any other information pops up. If not, I will accept your answer. $\endgroup$
    – czwang
    Commented Oct 22, 2019 at 0:00
  • 3
    $\begingroup$ Anecdotally, I was originally told that the three peaks of the letter W stood for the positions of the single '1' in each of the standard basis components. $\endgroup$ Commented Oct 23, 2019 at 8:40
  • 3
    $\begingroup$ @NieldeBeaudrap ha! We could write the $|W\rangle$ state as the $|Ш\rangle$ state! $\endgroup$ Commented Oct 29, 2019 at 14:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.