Stochastic and deterministic attenuation of one beam in the neutron interferometer

Experiments are reported, where one of the beams inside the neutron interferometer was attenuated in three different ways: by partially absorbing gold or indium foils, by a slow beam chopper and by a fine cadmium lattice. When the attenuation was the same the different methods still had a different effect on the amplitude of the interference pattern. This counter intuitive result can be formally explained in a quantum mechanical analysis which nicely illuminates how the history of a neutron affects its wave function.