Miura transform for W-algebras of classical types can be found in e.g. Sec. 6.3.3 of Bouwknegt-Schoutens. Is there a similar explicit Miura transform for W-algebras of exceptional types, say, E6? It's 20 years since the review by B-S, so I'd hope somebody worked this out ...


Yes, for the "quasi-classical" case(i.e. for the case when the $W$-algebra is commutative, which occurs when the level is either infinite or critical) it was defined by Drinfeld and Sokolov long time ago; you can look at Section 4 of http://arxiv.org/PS_cache/math/pdf/0305/0305216v1.pdf for a good review.

For the "quantum" case (i.e. for arbitrary level) it was studied by Feigin and Frenkel, but I am not sure what the right reference is; you can look for example at Section 4 of http://arxiv.org/PS_cache/hep-th/pdf/9408/9408109v1.pdf, but there should be more modern references. In fact, the main tool in the work of Feigin and Frenkel is the screening operators, which describe the $W$-algebra explicitly as a subalgebra of (the vertex operator algebra associated to) the Heisenberg algebra (where the embedding to the Heisenberg algebra is the Miura transformation).

  • $\begingroup$ Thank you, but my main problem is to explicitly write down the subalgebra commuting with the screening operators. For A and D, it's done by Fateev-Zamolodchikov and Fateev-Lukyanov. Their forms are quite useful because it can be readily implemented in a computer algebra system. I just want to perform a few stupid calculation inside W-algebra of type E6, but I first need to realize it inside computer. $\endgroup$ – Yuji Oct 26 '11 at 4:26
  • 2
    $\begingroup$ Since I don't believe in explicit formulas, I won't be able to say anything intelligent here:) One remark, though: you can describe the image of the W-algebra without the screening operators. It is just equal to the intersection over all simple roots of things like Virasoro$\otimes$Heisenberg of smaller rank (I hope it is clear what I mean) $\endgroup$ – Alexander Braverman Oct 26 '11 at 5:48
  • $\begingroup$ Yes you're right. Physicists cover their lack of deep thinking by lots of explicit calculation:p I've been using that approach to find generators of W(E6), but that's still quite messy. That's why I asked the question here. $\endgroup$ – Yuji Oct 26 '11 at 6:01
  • $\begingroup$ Do you want just generators, or generators and relations? $\endgroup$ – Alexander Braverman Oct 26 '11 at 6:07
  • $\begingroup$ I think he wants the fields for each exponent of $E6$ together with their OPE. I don't think you'll find those Yuji, at least at the principal nilpotent. In the case of the minimal nilpotent, Kac and Wakimoto have explicit formulas in this paper $\endgroup$ – Reimundo Heluani Oct 26 '11 at 9:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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