New branches of the essential spectrum of a family of 33 operator matrices

Аннотация

We consider a family of 33 operator matrices H(K) , d d K T : (; ] associated with the energy operator of a system of three non conserved number of lattice particles. We describe the essential spectrum of spectrum of H(K) via the spectrum of a family of generalized Friedrichs models and define its new branches. It is shown that the essential spectrum of H(K) consists the union of at most three bounded closed intervals.