Berry phase from a quantum Zeno effect

We exhibit a specific implementation of the creation of geometrical phase t hrough the state-space evolution generated by the dynamic quantum Zeno effe ct. That is, a system is guided through a closed loop in Hilbert space by m eans a sequence of closely spaced projections leading to a phase difference with respect to the original state. Our goal is the proposal of a specific experimental setup in which this phase could be created and observed. To t his end we study the case of neutron spin, examine the practical aspects of realizing the 'projections', and estimate the difference between the ideal ized projections and the experimental implementation. (C) 1999 Elsevier Sci ence B.V. All rights reserved.