DEPHASING IN NEUTRON INTERFEROMETRY

Wigner functions are used to describe various dephasing effects in neu tron interferometry which are caused by thickness variations and densi ty fluctuations of the phase shifter and by variations of the beam par ameters. It will be shown that separated coherent Schrodinger-cat-like states, which exist when large phase shifts are applied, are extremel y fragile and sensitive to any kind of imperfections. The related deph asing factor depends quadratically on the spatial separation of the co herent states which permits the definition of an upper limit of feasib le coherent packet separation. The results show that dephasing is an u navoidable effect caused by intrinsic fluctuations inherent to any phy sical system.