Conformal blocks in 2D CFTs

Question

I have studied conformal field theories in two dimensions and I understand the basic idea behind conformal blocks too. But I never completely realized what they are when it comes to computing them. Can someone explain at least one concrete example or refer to some articles where it has been done for a particular theory.

This post imported from StackExchange Physics at 2015-11-01 18:14 (UTC), posted by SE-user pinu

Comments

Possible duplicate: physics.stackexchange.com/q/1799/2451

This post imported from StackExchange Physics at 2015-11-01 18:14 (UTC), posted by SE-user Qmechanic

Answer 1

It can be rather involved. A lot of technical progress as been on this subject leading up to the modern conformal bootstrap work. Something you can exploit is that these functions should behave like correlation functions and thus are eigenfunctions of the conformal Casimir. That gives you differential equations which in some cases, especially in $D=2$ and $D=4$, you can solve.

See: http://arxiv.org/abs/hep-th/0309180 and http://arxiv.org/abs/1108.6194

This post imported from StackExchange Physics at 2015-11-01 18:14 (UTC), posted by SE-user SM Kravec

Comments

Thanks a lot! References look very useful. Can you say something about what is virasoro conformal block..

This post imported from StackExchange Physics at 2015-11-01 18:14 (UTC), posted by SE-user pinu

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So, as you may know, in 2D conformal symmetry is large. The above is speaking (mostly) about the \emph{global} conformal group, with generators $L_{-1} , L_{0} , L_{1}$, and its primaries as that's what relevant for $D > 2$. In 2D CFT these are often referred to as "quasi-primaries". Virasoro conformal blocks are the objects which contain information about decedents from primaries of the full Virasoro symmetry. Again they're difficult to compute, see arxiv.org/abs/1502.07742, arxiv.org/abs/1501.05315, and the phone book.

This post imported from StackExchange Physics at 2015-11-01 18:14 (UTC), posted by SE-user SM Kravec