Coherent scattering in non relativistic quantum mechanics

In this paper we give a pedagogical explanation of coherence effects in non relativistic scattering processes. Coherent scattering is important not only because it is a clear manifestation of the wave character of the interaction in these regimes, but also because it helps in increasing the cross section and thus the observable effects. We show under which conditions a particle scatters coherently on a multi-particle system. In a nutshell, in order to have coherent scattering, the incident particle has not to resolve the internal structure of the composite system. We show that the above condition is satisfied when the de Broglie length of the incident particle is much larger than the size of the system.