Friday, May 3, 2002, 16:00
WHGA Auditorium
Prof. H. Rauch, Atominstitut Wien
Abstract:
Neutrons are massive particles which couple to gravitational, nuclear and electro-magnetic interactions and they are
sensitive to topological effects, as well. Therefore they are a proper tool for testing
quantum
mechanics, especially because widely separated coherent beams can be
produced and influenced inside perfect crystal interferometers. Spinor symmetry and
spin superposition experiments have been performed on a rather fundamental
level. Recent experiments have shown that interference effects can be revived even
when the
overall interference pattern has lost its contrast. Related
post-selection experiments shed a new light on questions of quantum non-locality and
support the request for more complete quantum measurements in future. Typical
Schroedinger cat-like states have been identified and their sensitivity against any kind
of fluctuations and dissipative effects can be discussed. It will also be shown
that topological phases are important ingredients of quantum mechanics. Most
recently a confinement induced phase has been measured which appears when
neutrons pass through narrow slits and do even not touch the walls. With a perfect
crystal resonator system neutron can be trapped for several seconds and successive
measurements can be made. This permits the realization of Zeno effect like
experiments where a quantum state can be frozen in its initial state when the decay
state is continuously observed.