What does an observed quantum system reveal to its observer?
Institut für Laser-Physik, Universität Hamburg,
Jungiusstr. 9, 20355 Hamburg, Germany
Corresponding author: a email@example.com
Revised: 28 February 2001
Published online: 15 June 2001
The evolution of a quantum system under observation becomes retarded or even impeded. We review this "quantum Zeno effect"in the light of the criticism that has been raised upon a previous attempt to demonstrate it, of later reexaminations of both the projection postulate and the significance of the observations, and of the results of a recent experiment on an individual cold atom. Here, the micro-state of the quantum system gets unveiled with the observation, and the effect of measurement is no longer mixed up with dephasing the object's wave function by the reactive effect of the detection. A procedure is outlined that promises to provide, by observation, an upper limit for the delay of even an exponential decay.
PACS: 03.65.Bz – Foundations, theory of measurement, miscellaneous theories (including Aharonov-Bohm effect, Bell inequalities, Berry's phase) / 32.80.-t – Photon interactions with atoms / 42.50.Ct – Quantum description of interaction of light and matter; related experiments
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001