TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.11.5.089
TI  - Analytic conformal bootstrap and Virasoro primary fields in the Ashkin-Teller model
PY  - 2021/11/09
UR  - https://www.scipost.org/SciPostPhys.11.5.089
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 11
IS  - 5
SP  - 089
A1  - Nemkov, Nikita
AU  - Ribault, Sylvain
AB  - We revisit the critical two-dimensional Ashkin-Teller model, i.e. the $\mathbb{Z}_2$ orbifold of the compactified free boson CFT at $c=1$. We solve the model on the plane by computing its three-point structure constants and proving crossing symmetry of four-point correlation functions. We do this not only for affine primary fields, but also for Virasoro primary fields, i.e. higher twist fields and degenerate fields. This leads us to clarify the analytic properties of Virasoro conformal blocks and fusion kernels at $c=1$. We show that blocks with a degenerate channel field should be computed by taking limits in the central charge, rather than in the conformal dimension. In particular, Al. Zamolodchikov's simple explicit expression for the blocks that appear in four-twist correlation functions is only valid in the non-degenerate case: degenerate blocks, starting with the identity block, are more complicated generalized theta functions.
ER  -

@Article{10.21468/SciPostPhys.11.5.089,
	title={{Analytic conformal bootstrap and Virasoro primary fields in the Ashkin-Teller model}},
	author={Nikita Nemkov and Sylvain Ribault},
	journal={SciPost Phys.},
	volume={11},
	pages={089},
	year={2021},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.11.5.089},
	url={https://scipost.org/10.21468/SciPostPhys.11.5.089},
}