Defect Partition Function from TDLs in Commutant Pairs

Abstract

We study topological defect lines in two character rational conformal field theories. Among them one set of two character theories are commutant pairs in $E_{8,1}$ conformal field theory. Using these defect lines we construct defect partition function in the $E_8$ theory. We find that the defects preserve only a part of the $E_8$ current algebra symmetry. We also determine the defect partition function in $c=24$ CFT using these defects lines of 2 character theories and we find that these defects preserve all current algebra symmetries of $c=24$ CFT.Comment: 20 pages, typos corrected, some references adde