A note on the identity module in CFTs
arXiv:2109.05050 · doi:10.21468/SciPostPhys.12.3.100
Abstract
It has long been understood that non-trivial Conformal Field Theories (CFTs) with vanishing central charge () are logarithmic. So far however, the structure of the identity module -- the (left and right) Virasoro descendants of the identity field -- had not been elucidated beyond the stress-energy tensor and its logarithmic partner (the solution of the " catastrophe"). In this paper, we determine this structure together with the associated OPE of primary fields up to level for polymers and percolation CFTs. This is done by taking the limit of and Potts models and combining recent results from the bootstrap with arguments based on conformal invariance and self-duality. We find that the structure contains a rank-3 Jordan cell involving the field , and is identical for polymers and percolation. It is characterized in part by the common value of a non-chiral logarithmic coupling .
24 pages. v2: comments added, typos corrected. v3: comments in footnote 7 improved