QUANTUM ZENO EFFECT AND LIGHT-DARK PERIODS FOR A SINGLE-ATOM

The quantum Zeno effect (QZE) predicts a slow-down of the time develop ment of a system under rapidly repeated ideal measurements, and experi mentally this was tested for an ensemble of atoms using short laser pu lses for non-selective state measurements. Here we consider such pulse s for selective measurements on a single system. Each probe pulse will cause a burst of fluorescence or no fluorescence. If the probe pulses were strictly ideal measurements, the QZE would predict periods of fl uorescence bursts alternating with periods of no fluorescence (light a nd dark periods) which would become longer and longer with increasing frequency of the measurements. The non-ideal character of the measurem ents is taken into account by incorporating the laser pulses in the in teraction, and this is used to determine the corrections to the ideal case. In the limit, when the time, Delta t, between the laser pulses g oes to zero, no freezing occurs but instead we show convergence to the familiar macroscopic light and dark periods of the continuously drive n Dehmelt system An experiment of this type should be feasible for a s ingle atom or ion in a trap.