Decoherence, dephasing and depolarization

By means of a quantum optical description the connection between decoherenc e, dephasing and depolarization is shown. The transition from a quantum sta te to a mixture is caused by the interaction of the neutron with fluctuatin g and dissipative forces in matter or magnetic fields. An analytical descri ption of this effect provides the basis for phase sensitive investigations of condensed matter with polarized neutrons. Analogies between the coherenc e function and the beam polarization will be discussed. (C) 1999 Elsevier S cience B.V. All rights reserved.