DECOHERENCE IN NEUTRON INTERFEROMETRY AT LOW TRANSMISSION PROBABILITY

We present a simplified and improved analysis of some recent experiments of neutron interferometry at low transmission probability. It is shown that both the density fluctuations of the elementary constituents of the absorber and the uncertainties in the sample thickness can be analyzed with the same formalism, and that they lead to a reduction of the visibility of the interference pattern. The effect is quantitatively estimated in the Gaussian case. In the context of quantum measurements, the process can be viewed as a partial dephasing characterized by the decoherence parameter. Possible experimental tests are proposed