SCHROEDINGER CAT-LIKE NEUTRON STATES AND WIGNER FUNCTION FORMULATION OF INTERFEROMETRY AND SPIN-ECHO EXPERIMENTS

The formalism of quantum optics can be adapted to advanced neutron opt ics. Measurements and calculations have identified a characteristic co herent and squeezed state behaviour for neutron states and a transfer of coherence features between ordinary and momentum space. In certain cases. the neutron occupies two well-separated regions in ordinary spa ce which are coupled in momentum space giving a clear fingerprint of a Schroedinger cat-like quantum state. The visualization of such states can be achieved by a Wigner function representation where it becomes obvious that wave function tomography becomes feasible. Hence, spin-ec ho experiments are Ramse-Borde interference experiments in the longitu dinal direction; they can be described by Wigner functions as well. Ad ditionally, it will be shown that Schroedinger cat-like states are rat her fragile against any dissipative force from the environment, (C) 19 98 Elsevier Science B.V. All rights reserved.