HINDERED DECAY - QUANTUM ZENO EFFECT THROUGH ELECTROMAGNETIC-FIELD DOMINATION

The lifetime of an unstable atom can be extended by watching it closel y, i.e., illuminating it with an intense electromagnetic field of appr opriate frequency. This is an example of ''dominated evolution'' and i s closely related to the so-called ''quantum Zeno effect.'' For a meta stable atom bathed in a laser beam at the frequency of another of its transitions, we obtain an expression for the modified lifetime as a fu nction of beam intensity. This provides an example of the quantum Zeno effect on a truly decaying system, and also should be useful for prob ing short distance features of atomic wave functions.