Perturbed Defects and T-Systems in Conformal Field Theory

Understand

Defect lines in conformal field theory can be perturbed by chiral defect fields.

• If the unperturbed defects satisfy su(2)-type fusion rules, the operators associated to the perturbed defects are shown to obey functional relations known from the study of integrable models as T-systems.
• The procedure is illustrated for Virasoro minimal models and for Liouville theory.