Global torus blocks in the necklace channel
Mikhail Pavlov
TL;DR
This work develops global torus conformal blocks in the necklace channel for multi-point correlators in a $2$-D CFT, expressing necklace blocks through $(N+2)$-point comb-channel blocks and enforcing Casimir equations. By imposing special conditions on the conformal dimensions, the authors obtain explicit polynomial block functions, starting from the $1$-pt case and building up to $N$-pt blocks. They show that the necklace blocks satisfy the Casimir equations and relate the necklace construction to OPE/comb-channel decompositions, highlighting structure such as factorization in simple cases and polynomial corrections controlled by a finite set of parameters. The results provide a concrete handle on torus necklace blocks and open avenues for AdS/CFT applications and generalizations to degenerate or supersymmetric blocks.
Abstract
We continue studying of global conformal blocks on the torus in a special (necklace) channel. Functions of such multi-point blocks are explicitly found under special conditions on the blocks' conformal dimensions. We have verified that these blocks satisfy the Casimir equations, which were derived in previous studies.
