On the spectral theory of singular Dirac type Hamiltonians

Abstract. We introduce a class of matrix valued pseudo-differential opera-tors that admit scalar locally conjugate operators (in the sense of E. Mourre) and we give a general method of study of singular perturbations of such oper-ators. In particular, we develop the spectral and scattering theory for a class of hamiltonians which contains the Dirac operators with arbitrary Coulomb singularities