Novel defect universality classes from interacting RG interfaces

Abstract We search for new defect universality classes by considering localised interactions placed on an renormalisation group (RG) interface separating two interacting multiscalar CFTs in 4 − ε dimensions. Studying interactions spread throughout the entire interface as well as defects restricted to lines and surfaces within the interface, we find that this setup leads to a great number of additional physical fixed points in the space of conformal defects. At one loop it is possible to interpret these fixed points as coming from defects placed within a single bulk whose interaction is an average of the two sides. This averaging means that it is possible to identify conformal defects with considerably less global symmetry than was possible beforehand. We finally compute conformal data for this setup, and find the free energy associated with these RG interfaces.