2D fermion on the strip with boundary defects as a CFT with excited spin fields

We consider a two-dimensional fermion on the strip in the presence of an arbitrary number of zero-dimensional boundary changing defects. We show that the theory is still conformal with time dependent stress-energy tensor and that the allowed defects can be understood as excited spin fields. Finally we compute correlation functions involving these excited spin fields without using bosonization. (C) 2021 The Author(s). Published by Elsevier B.V.