DYNAMICS BY MEASUREMENT - AHARONOV INVERSE QUANTUM ZENO EFFECT

The quantum Zeno effect is known as the inhibition of a system's rever sible dynamics by frequent measurements. Aharonov and Vardi [Phys. Rev . D 21, 2235 (1980)] proposed a scheme intimately related to the quant um Zeno effect. They showed that, by performing a dense sequence of me asurements along a presumed path, the system is found to follow this-a rbitrarily chosen-trajectory. The proof was based on the von Neumann p rojection hypothesis. In this paper we investigate whether this effect still holds if we model a realistic measurement process instead of th e artificial instantaneous von Neumann collapse. We test the orientati on of the Moch vector of a two-level system using a third level and re sonance fluorescence as the measuring apparatus. Therefore we are able to use a dynamical collapse governed by the three-level master equati ons. We show that a sequence of orientation measurements designed to m onitor a particular trajectory indeed induces a dynamics exactly along this trajectory.