Abelian bosonization approach to quantum impurity problems

Using Abelian bosonization, we develop a simple and powerful method to calculate the correlation functions of the two channel Kondo model and its variants. The method can also be used to identify all the possible boundary fixed points and their maximum symmetry, to calculate straightforwardly the finite size spectra, and to demonstrate the physical picture at the boundary explicitly. Comparisons with the non-Abelian bosonization method are made. Some fixed points corresponding to four pieces of bulk fermions coupled to s = 1/2 impurity are listed.