• quantum electrodynamics
• scattering

This thesis is devoted to the analysis of solvable hamiltonian models, with the purpose of
understanding and possibly filling the gap
that still separates the standard methods,
used to circumvent the infrared divergences occurring in the local and covariant
Feynman-Dyson expansion of Quantum Electrodynamics, from a formulation of scattering in which the non-perturbative features of the infrared
problem are taken into account.