The solutions of Heisenberg equations and two-particles eigenvalue problems for nonrelativistic models of current-current fermion interaction and N, Θ model are obtained in the frameworks of dynamical mapping method. The equivalence of different types of dynamical mapping is shown. The connection between renormalization procedure and theory of selfadjoint extensions is elucidated.
General considerationThe main problem of QFT follows from the fact that any solutions of Heisenberg equations (HE) are the operator distributions which products, always appearing in that equations, are ill-defined.So, the correct definition of field equations (and Hamiltonian itself) implies some knowledge about qualitative properties of its solutions which in their turn depend on the form of these equations by a very singular manner. The usual way to go out from this closed circle is connected with perturbation theory. It is based on the assumption that product of Heisenberg fields (HF) may be defined as well as for the free ones and solution of HE may be obtained by perturbation in the Fock space of renormalized free fields. However, it is impossible on such a way to work with nonrenormalizable theory and to understand the origin of the bound states. We consider another possibility which is based on the idea of dynamical mapping and reduce the product of HF to the normal ordering for the product of the physical fields. It is originated from the works of R.Haag In this approach the problem of making a sense for formal expression of HF:for Hamiltonian given as a functional H = H [Ψ( x, t)], is divided on two parts. The first one is the construction of the following operator realization of the initial fields Ψ( x, t 0 ) = Ψ[ψ] via physical fields ψ( x, t) ≡ ψ A α ( k) , which, on the one hand, should be consistent with CCR (CAR) (α = 1, 2) {Ψ α ( x, t) , Ψ β ( y, t)} = 0 = {ψ α ( x, t) , ψ β ( y, t)}, {Ψ α ( x, t) , Ψ † β ( y, t)} = δ 3 ( x − y) δ αβ = {ψ α ( x, t) , ψ † β ( y, t)}, {A α ( k) , A β ( q)} = 0; {A α ( k) , A † β ( q)} = δ 3 ( k − q) δ αβ ,