From Quantum Field Theory to the Contemporary Quantum Mechanics

In this talk we remind how the notion of the so-called clothed particles, put forward in relativistic quantum field theory by Greenberg and Schweber, can be used via the method of unitary clothing transformations (shortly, the UCT method) when finding the eigenstates of the total Hamiltonian H in case of interacting fields with the Yukawa - type couplings. In general, the UCT method is aimed at reduction of the exact eigenvalue problem in the primary Fock space to the model-space problems in the corresponding Hilbert spaces of the contemporary quantum mechanics. In this context we consider an approximate treatment of the physical vacuum, the observable one-particle and two-particle bound and scattering states.