Abstract:
It is shown that the translationally invariant limit ot the boson field in the Lee
model exists and is equal to the free field. As a result, the translationally invariant
scattering matrix exists also, but it is equal to the identity. The calculation of the same
matrix by the standard perturbation theory procedure gives rise to divergent expressions.
This means that we have demonstrated in the particular case that the divergencies
of the quantum field theory can be caused by using of the perturbation theory.